/*
OneLoneCoder.com - 3D Graphics Part #4 - Texturing & Depth Buffers
"Tredimensjonal Grafikk" - @Javidx9
!!! MODIFIED TO SUITE PIXEL GAME ENGINE !!!
!!! EXAMINE LINE 70 BEFORE COMPILING !!!
License (OLC-3)
~~~~~~~~~~~~~~~
Copyright 2018-2019 OneLoneCoder.com
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions or derivations of source code must retain the above
copyright notice, this list of conditions and the following disclaimer.
2. Redistributions or derivative works in binary form must reproduce
the above copyright notice. This list of conditions and the following
disclaimer must be reproduced in the documentation and/or other
materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Background
~~~~~~~~~~
3D Graphics is an interesting, visually pleasing suite of algorithms. This is the
first video in a series that will demonstrate the fundamentals required to
build your own software based 3D graphics systems.
Video
~~~~~
https://youtu.be/ih20l3pJoeU
https://youtu.be/XgMWc6LumG4
https://youtu.be/HXSuNxpCzdM
https://youtu.be/nBzCS-Y0FcY
Author
~~~~~~
Twitter: @javidx9
Blog: http://www.onelonecoder.com
Discord: https://discord.gg/WhwHUMV
Last Updated: 26/05/2019
*/
// PLEASE NOTE! The video shows the Spyro The Dragon Level - I can't redistribute that
// so this file is configured to show the textured Jario cube. Please ensure you have
// downloaded the "Jario.spr" file from
// Comment out this line to run "mountains" demo from part 3
#define DO_TEXTURE_DEMO
#define OLC_PGE_APPLICATION
#include "olcPixelGameEngine.h"
#include <fstream>
#include <strstream>
#include <algorithm>
#include <string>
using namespace std;
// Created a 2D structure to hold texture coordinates
struct vec2d
{
float u = 0;
float v = 0;
float w = 1;
};
struct vec3d
{
float x = 0;
float y = 0;
float z = 0;
float w = 1; // Need a 4th term to perform sensible matrix vector multiplication
};
struct triangle
{
vec3d p[3];
vec2d t[3]; // added a texture coord per vertex
olc::Pixel col;
};
struct mesh
{
vector<triangle> tris;
bool LoadFromObjectFile(string sFilename, bool bHasTexture = false)
{
ifstream f(sFilename);
if (!f.is_open())
return false;
// Local cache of verts
vector<vec3d> verts;
vector<vec2d> texs;
while (!f.eof())
{
char line[128];
f.getline(line, 128);
strstream s;
s << line;
char junk;
if (line[0] == 'v')
{
if (line[1] == 't')
{
vec2d v;
s >> junk >> junk >> v.u >> v.v;
// A little hack for the spyro texture
//v.u = 1.0f - v.u;
//v.v = 1.0f - v.v;
texs.push_back(v);
}
else
{
vec3d v;
s >> junk >> v.x >> v.y >> v.z;
verts.push_back(v);
}
}
if (!bHasTexture)
{
if (line[0] == 'f')
{
int f[3];
s >> junk >> f[0] >> f[1] >> f[2];
tris.push_back({ verts[f[0] - 1], verts[f[1] - 1], verts[f[2] - 1] });
}
}
else
{
if (line[0] == 'f')
{
s >> junk;
string tokens[6];
int nTokenCount = -1;
while (!s.eof())
{
char c = s.get();
if (c == ' ' || c == '/')
nTokenCount++;
else
tokens[nTokenCount].append(1, c);
}
tokens[nTokenCount].pop_back();
tris.push_back({ verts[stoi(tokens[0]) - 1], verts[stoi(tokens[2]) - 1], verts[stoi(tokens[4]) - 1],
texs[stoi(tokens[1]) - 1], texs[stoi(tokens[3]) - 1], texs[stoi(tokens[5]) - 1] });
}
}
}
return true;
}
};
struct mat4x4
{
float m[4][4] = { 0 };
};
class olcEngine3D : public olc::PixelGameEngine
{
public:
olcEngine3D()
{
sAppName = "3D Demo";
}
private:
mesh meshCube;
mat4x4 matProj; // Matrix that converts from view space to screen space
vec3d vCamera; // Location of camera in world space
vec3d vLookDir; // Direction vector along the direction camera points
float fYaw; // FPS Camera rotation in XZ plane
float fTheta; // Spins World transform
olc::Sprite *sprTex1;
vec3d Matrix_MultiplyVector(mat4x4 &m, vec3d &i)
{
vec3d v;
v.x = i.x * m.m[0][0] + i.y * m.m[1][0] + i.z * m.m[2][0] + i.w * m.m[3][0];
v.y = i.x * m.m[0][1] + i.y * m.m[1][1] + i.z * m.m[2][1] + i.w * m.m[3][1];
v.z = i.x * m.m[0][2] + i.y * m.m[1][2] + i.z * m.m[2][2] + i.w * m.m[3][2];
v.w = i.x * m.m[0][3] + i.y * m.m[1][3] + i.z * m.m[2][3] + i.w * m.m[3][3];
return v;
}
mat4x4 Matrix_MakeIdentity()
{
mat4x4 matrix;
matrix.m[0][0] = 1.0f;
matrix.m[1][1] = 1.0f;
matrix.m[2][2] = 1.0f;
matrix.m[3][3] = 1.0f;
return matrix;
}
mat4x4 Matrix_MakeRotationX(float fAngleRad)
{
mat4x4 matrix;
matrix.m[0][0] = 1.0f;
matrix.m[1][1] = cosf(fAngleRad);
matrix.m[1][2] = sinf(fAngleRad);
matrix.m[2][1] = -sinf(fAngleRad);
matrix.m[2][2] = cosf(fAngleRad);
matrix.m[3][3] = 1.0f;
return matrix;
}
mat4x4 Matrix_MakeRotationY(float fAngleRad)
{
mat4x4 matrix;
matrix.m[0][0] = cosf(fAngleRad);
matrix.m[0][2] = sinf(fAngleRad);
matrix.m[2][0] = -sinf(fAngleRad);
matrix.m[1][1] = 1.0f;
matrix.m[2][2] = cosf(fAngleRad);
matrix.m[3][3] = 1.0f;
return matrix;
}
mat4x4 Matrix_MakeRotationZ(float fAngleRad)
{
mat4x4 matrix;
matrix.m[0][0] = cosf(fAngleRad);
matrix.m[0][1] = sinf(fAngleRad);
matrix.m[1][0] = -sinf(fAngleRad);
matrix.m[1][1] = cosf(fAngleRad);
matrix.m[2][2] = 1.0f;
matrix.m[3][3] = 1.0f;
return matrix;
}
mat4x4 Matrix_MakeTranslation(float x, float y, float z)
{
mat4x4 matrix;
matrix.m[0][0] = 1.0f;
matrix.m[1][1] = 1.0f;
matrix.m[2][2] = 1.0f;
matrix.m[3][3] = 1.0f;
matrix.m[3][0] = x;
matrix.m[3][1] = y;
matrix.m[3][2] = z;
return matrix;
}
mat4x4 Matrix_MakeProjection(float fFovDegrees, float fAspectRatio, float fNear, float fFar)
{
float fFovRad = 1.0f / tanf(fFovDegrees * 0.5f / 180.0f * 3.14159f);
mat4x4 matrix;
matrix.m[0][0] = fAspectRatio * fFovRad;
matrix.m[1][1] = fFovRad;
matrix.m[2][2] = fFar / (fFar - fNear);
matrix.m[3][2] = (-fFar * fNear) / (fFar - fNear);
matrix.m[2][3] = 1.0f;
matrix.m[3][3] = 0.0f;
return matrix;
}
mat4x4 Matrix_MultiplyMatrix(mat4x4 &m1, mat4x4 &m2)
{
mat4x4 matrix;
for (int c = 0; c < 4; c++)
for (int r = 0; r < 4; r++)
matrix.m[r][c] = m1.m[r][0] * m2.m[0][c] + m1.m[r][1] * m2.m[1][c] + m1.m[r][2] * m2.m[2][c] + m1.m[r][3] * m2.m[3][c];
return matrix;
}
mat4x4 Matrix_PointAt(vec3d &pos, vec3d &target, vec3d &up)
{
// Calculate new forward direction
vec3d newForward = Vector_Sub(target, pos);
newForward = Vector_Normalise(newForward);
// Calculate new Up direction
vec3d a = Vector_Mul(newForward, Vector_DotProduct(up, newForward));
vec3d newUp = Vector_Sub(up, a);
newUp = Vector_Normalise(newUp);
// New Right direction is easy, its just cross product
vec3d newRight = Vector_CrossProduct(newUp, newForward);
// Construct Dimensioning and Translation Matrix
mat4x4 matrix;
matrix.m[0][0] = newRight.x; matrix.m[0][1] = newRight.y; matrix.m[0][2] = newRight.z; matrix.m[0][3] = 0.0f;
matrix.m[1][0] = newUp.x; matrix.m[1][1] = newUp.y; matrix.m[1][2] = newUp.z; matrix.m[1][3] = 0.0f;
matrix.m[2][0] = newForward.x; matrix.m[2][1] = newForward.y; matrix.m[2][2] = newForward.z; matrix.m[2][3] = 0.0f;
matrix.m[3][0] = pos.x; matrix.m[3][1] = pos.y; matrix.m[3][2] = pos.z; matrix.m[3][3] = 1.0f;
return matrix;
}
mat4x4 Matrix_QuickInverse(mat4x4 &m) // Only for Rotation/Translation Matrices
{
mat4x4 matrix;
matrix.m[0][0] = m.m[0][0]; matrix.m[0][1] = m.m[1][0]; matrix.m[0][2] = m.m[2][0]; matrix.m[0][3] = 0.0f;
matrix.m[1][0] = m.m[0][1]; matrix.m[1][1] = m.m[1][1]; matrix.m[1][2] = m.m[2][1]; matrix.m[1][3] = 0.0f;
matrix.m[2][0] = m.m[0][2]; matrix.m[2][1] = m.m[1][2]; matrix.m[2][2] = m.m[2][2]; matrix.m[2][3] = 0.0f;
matrix.m[3][0] = -(m.m[3][0] * matrix.m[0][0] + m.m[3][1] * matrix.m[1][0] + m.m[3][2] * matrix.m[2][0]);
matrix.m[3][1] = -(m.m[3][0] * matrix.m[0][1] + m.m[3][1] * matrix.m[1][1] + m.m[3][2] * matrix.m[2][1]);
matrix.m[3][2] = -(m.m[3][0] * matrix.m[0][2] + m.m[3][1] * matrix.m[1][2] + m.m[3][2] * matrix.m[2][2]);
matrix.m[3][3] = 1.0f;
return matrix;
}
vec3d Vector_Add(vec3d &v1, vec3d &v2)
{
return { v1.x + v2.x, v1.y + v2.y, v1.z + v2.z };
}
vec3d Vector_Sub(vec3d &v1, vec3d &v2)
{
return { v1.x - v2.x, v1.y - v2.y, v1.z - v2.z };
}
vec3d Vector_Mul(vec3d &v1, float k)
{
return { v1.x * k, v1.y * k, v1.z * k };
}
vec3d Vector_Div(vec3d &v1, float k)
{
return { v1.x / k, v1.y / k, v1.z / k };
}
float Vector_DotProduct(vec3d &v1, vec3d &v2)
{
return v1.x*v2.x + v1.y*v2.y + v1.z * v2.z;
}
float Vector_Length(vec3d &v)
{
return sqrtf(Vector_DotProduct(v, v));
}
vec3d Vector_Normalise(vec3d &v)
{
float l = Vector_Length(v);
return { v.x / l, v.y / l, v.z / l };
}
vec3d Vector_CrossProduct(vec3d &v1, vec3d &v2)
{
vec3d v;
v.x = v1.y * v2.z - v1.z * v2.y;
v.y = v1.z * v2.x - v1.x * v2.z;
v.z = v1.x * v2.y - v1.y * v2.x;
return v;
}
vec3d Vector_IntersectPlane(vec3d &plane_p, vec3d &plane_n, vec3d &lineStart, vec3d &lineEnd, float &t)
{
plane_n = Vector_Normalise(plane_n);
float plane_d = -Vector_DotProduct(plane_n, plane_p);
float ad = Vector_DotProduct(lineStart, plane_n);
float bd = Vector_DotProduct(lineEnd, plane_n);
t = (-plane_d - ad) / (bd - ad);
vec3d lineStartToEnd = Vector_Sub(lineEnd, lineStart);
vec3d lineToIntersect = Vector_Mul(lineStartToEnd, t);
return Vector_Add(lineStart, lineToIntersect);
}
int Triangle_ClipAgainstPlane(vec3d plane_p, vec3d plane_n, triangle &in_tri, triangle &out_tri1, triangle &out_tri2)
{
// Make sure plane normal is indeed normal
plane_n = Vector_Normalise(plane_n);
// Return signed shortest distance from point to plane, plane normal must be normalised
auto dist = [&](vec3d &p)
{
vec3d n = Vector_Normalise(p);
return (plane_n.x * p.x + plane_n.y * p.y + plane_n.z * p.z - Vector_DotProduct(plane_n, plane_p));
};
// Create two temporary storage arrays to classify points either side of plane
// If distance sign is positive, point lies on "inside" of plane
vec3d* inside_points[3]; int nInsidePointCount = 0;
vec3d* outside_points[3]; int nOutsidePointCount = 0;
vec2d* inside_tex[3]; int nInsideTexCount = 0;
vec2d* outside_tex[3]; int nOutsideTexCount = 0;
// Get signed distance of each point in triangle to plane
float d0 = dist(in_tri.p[0]);
float d1 = dist(in_tri.p[1]);
float d2 = dist(in_tri.p[2]);
if (d0 >= 0) { inside_points[nInsidePointCount++] = &in_tri.p[0]; inside_tex[nInsideTexCount++] = &in_tri.t[0]; }
else {
outside_points[nOutsidePointCount++] = &in_tri.p[0]; outside_tex[nOutsideTexCount++] = &in_tri.t[0];
}
if (d1 >= 0) {
inside_points[nInsidePointCount++] = &in_tri.p[1]; inside_tex[nInsideTexCount++] = &in_tri.t[1];
}
else {
outside_points[nOutsidePointCount++] = &in_tri.p[1]; outside_tex[nOutsideTexCount++] = &in_tri.t[1];
}
if (d2 >= 0) {
inside_points[nInsidePointCount++] = &in_tri.p[2]; inside_tex[nInsideTexCount++] = &in_tri.t[2];
}
else {
outside_points[nOutsidePointCount++] = &in_tri.p[2]; outside_tex[nOutsideTexCount++] = &in_tri.t[2];
}
// Now classify triangle points, and break the input triangle into
// smaller output triangles if required. There are four possible
// outcomes...
if (nInsidePointCount == 0)
{
// All points lie on the outside of plane, so clip whole triangle
// It ceases to exist
return 0; // No returned triangles are valid
}
if (nInsidePointCount == 3)
{
// All points lie on the inside of plane, so do nothing
// and allow the triangle to simply pass through
out_tri1 = in_tri;
return 1; // Just the one returned original triangle is valid
}
if (nInsidePointCount == 1 && nOutsidePointCount == 2)
{
// Triangle should be clipped. As two points lie outside
// the plane, the triangle simply becomes a smaller triangle
// Copy appearance info to new triangle
out_tri1.col = in_tri.col;
// The inside point is valid, so keep that...
out_tri1.p[0] = *inside_points[0];
out_tri1.t[0] = *inside_tex[0];
// but the two new points are at the locations where the
// original sides of the triangle (lines) intersect with the plane
float t;
out_tri1.p[1] = Vector_IntersectPlane(plane_p, plane_n, *inside_points[0], *outside_points[0], t);
out_tri1.t[1].u = t * (outside_tex[0]->u - inside_tex[0]->u) + inside_tex[0]->u;
out_tri1.t[1].v = t * (outside_tex[0]->v - inside_tex[0]->v) + inside_tex[0]->v;
out_tri1.t[1].w = t * (outside_tex[0]->w - inside_tex[0]->w) + inside_tex[0]->w;
out_tri1.p[2] = Vector_IntersectPlane(plane_p, plane_n, *inside_points[0], *outside_points[1], t);
out_tri1.t[2].u = t * (outside_tex[1]->u - inside_tex[0]->u) + inside_tex[0]->u;
out_tri1.t[2].v = t * (outside_tex[1]->v - inside_tex[0]->v) + inside_tex[0]->v;
out_tri1.t[2].w = t * (outside_tex[1]->w - inside_tex[0]->w) + inside_tex[0]->w;
return 1; // Return the newly formed single triangle
}
if (nInsidePointCount == 2 && nOutsidePointCount == 1)
{
// Triangle should be clipped. As two points lie inside the plane,
// the clipped triangle becomes a "quad". Fortunately, we can
// represent a quad with two new triangles
// Copy appearance info to new triangles
out_tri1.col = in_tri.col;
out_tri2.col = in_tri.col;
// The first triangle consists of the two inside points and a new
// point determined by the location where one side of the triangle
// intersects with the plane
out_tri1.p[0] = *inside_points[0];
out_tri1.p[1] = *inside_points[1];
out_tri1.t[0] = *inside_tex[0];
out_tri1.t[1] = *inside_tex[1];
float t;
out_tri1.p[2] = Vector_IntersectPlane(plane_p, plane_n, *inside_points[0], *outside_points[0], t);
out_tri1.t[2].u = t * (outside_tex[0]->u - inside_tex[0]->u) + inside_tex[0]->u;
out_tri1.t[2].v = t * (outside_tex[0]->v - inside_tex[0]->v) + inside_tex[0]->v;
out_tri1.t[2].w = t * (outside_tex[0]->w - inside_tex[0]->w) + inside_tex[0]->w;
// The second triangle is composed of one of he inside points, a
// new point determined by the intersection of the other side of the
// triangle and the plane, and the newly created point above
out_tri2.p[0] = *inside_points[1];
out_tri2.t[0] = *inside_tex[1];
out_tri2.p[1] = out_tri1.p[2];
out_tri2.t[1] = out_tri1.t[2];
out_tri2.p[2] = Vector_IntersectPlane(plane_p, plane_n, *inside_points[1], *outside_points[0], t);
out_tri2.t[2].u = t * (outside_tex[0]->u - inside_tex[1]->u) + inside_tex[1]->u;
out_tri2.t[2].v = t * (outside_tex[0]->v - inside_tex[1]->v) + inside_tex[1]->v;
out_tri2.t[2].w = t * (outside_tex[0]->w - inside_tex[1]->w) + inside_tex[1]->w;
return 2; // Return two newly formed triangles which form a quad
}
}
float *pDepthBuffer = nullptr;
public:
bool OnUserCreate() override
{
pDepthBuffer = new float[ScreenWidth() * ScreenHeight()];
// Load object file
#ifdef DO_TEXTURE_DEMO
meshCube.tris = {
// SOUTH
{ 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// EAST
{ 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// NORTH
{ 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// WEST
{ 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// TOP
{ 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// BOTTOM
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
};
#else
meshCube.LoadFromObjectFile("mountains.obj");
#endif
sprTex1 = new olc::Sprite("zombie.png");
// Projection Matrix
matProj = Matrix_MakeProjection(90.0f, (float)ScreenHeight() / (float)ScreenWidth(), 0.1f, 1000.0f);
return true;
}
bool OnUserUpdate(float fElapsedTime) override
{
if (GetKey(olc::Key::UP).bHeld)
vCamera.y += 8.0f * fElapsedTime; // Travel Upwards
if (GetKey(olc::Key::DOWN).bHeld)
vCamera.y -= 8.0f * fElapsedTime; // Travel Downwards
// Dont use these two in FPS mode, it is confusing :P
if (GetKey(olc::Key::LEFT).bHeld)
vCamera.x -= 8.0f * fElapsedTime; // Travel Along X-Axis
if (GetKey(olc::Key::RIGHT).bHeld)
vCamera.x += 8.0f * fElapsedTime; // Travel Along X-Axis
///////
vec3d vForward = Vector_Mul(vLookDir, 8.0f * fElapsedTime);
// Standard FPS Control scheme, but turn instead of strafe
if (GetKey(olc::Key::W).bHeld)
vCamera = Vector_Add(vCamera, vForward);
if (GetKey(olc::Key::S).bHeld)
vCamera = Vector_Sub(vCamera, vForward);
if (GetKey(olc::Key::A).bHeld)
fYaw -= 2.0f * fElapsedTime;
if (GetKey(olc::Key::D).bHeld)
fYaw += 2.0f * fElapsedTime;
// Set up "World Tranmsform" though not updating theta
// makes this a bit redundant
mat4x4 matRotZ, matRotX;
#ifdef DO_TEXTURE_DEMO
fTheta += 1.0f * fElapsedTime; // Uncomment to spin me right round baby right round
#endif
matRotZ = Matrix_MakeRotationZ(fTheta * 0.5f);
matRotX = Matrix_MakeRotationX(fTheta);
mat4x4 matTrans;
matTrans = Matrix_MakeTranslation(0.0f, 0.0f, 5.0f);
mat4x4 matWorld;
matWorld = Matrix_MakeIdentity(); // Form World Matrix
matWorld = Matrix_MultiplyMatrix(matRotZ, matRotX); // Transform by rotation
matWorld = Matrix_MultiplyMatrix(matWorld, matTrans); // Transform by translation
// Create "Point At" Matrix for camera
vec3d vUp = { 0,1,0 };
vec3d vTarget = { 0,0,1 };
mat4x4 matCameraRot = Matrix_MakeRotationY(fYaw);
vLookDir = Matrix_MultiplyVector(matCameraRot, vTarget);
vTarget = Vector_Add(vCamera, vLookDir);
mat4x4 matCamera = Matrix_PointAt(vCamera, vTarget, vUp);
// Make view matrix from camera
mat4x4 matView = Matrix_QuickInverse(matCamera);
// Store triagles for rastering later
vector<triangle> vecTrianglesToRaster;
// Draw Triangles
for (auto tri : meshCube.tris)
{
triangle triProjected, triTransformed, triViewed;
// World Matrix Transform
triTransformed.p[0] = Matrix_MultiplyVector(matWorld, tri.p[0]);
triTransformed.p[1] = Matrix_MultiplyVector(matWorld, tri.p[1]);
triTransformed.p[2] = Matrix_MultiplyVector(matWorld, tri.p[2]);
triTransformed.t[0] = tri.t[0];
triTransformed.t[1] = tri.t[1];
triTransformed.t[2] = tri.t[2];
// Calculate triangle Normal
vec3d normal, line1, line2;
// Get lines either side of triangle
line1 = Vector_Sub(triTransformed.p[1], triTransformed.p[0]);
line2 = Vector_Sub(triTransformed.p[2], triTransformed.p[0]);
// Take cross product of lines to get normal to triangle surface
normal = Vector_CrossProduct(line1, line2);
// You normally need to normalise a normal!
normal = Vector_Normalise(normal);
// Get Ray from triangle to camera
vec3d vCameraRay = Vector_Sub(triTransformed.p[0], vCamera);
// If ray is aligned with normal, then triangle is visible
if (Vector_DotProduct(normal, vCameraRay) < 0.0f)
{
// Illumination
vec3d light_direction = { 0.0f, 1.0f, -1.0f };
light_direction = Vector_Normalise(light_direction);
// How "aligned" are light direction and triangle surface normal?
float dp = max(0.1f, Vector_DotProduct(light_direction, normal));
// Choose console colours as required (much easier with RGB)
triTransformed.col = olc::Pixel(dp * 255, dp * 255, dp * 255);
// Convert World Space --> View Space
triViewed.p[0] = Matrix_MultiplyVector(matView, triTransformed.p[0]);
triViewed.p[1] = Matrix_MultiplyVector(matView, triTransformed.p[1]);
triViewed.p[2] = Matrix_MultiplyVector(matView, triTransformed.p[2]);
triViewed.col = triTransformed.col;
triViewed.t[0] = triTransformed.t[0];
triViewed.t[1] = triTransformed.t[1];
triViewed.t[2] = triTransformed.t[2];
// Clip Viewed Triangle against near plane, this could form two additional
// additional triangles.
int nClippedTriangles = 0;
triangle clipped[2];
nClippedTriangles = Triangle_ClipAgainstPlane({ 0.0f, 0.0f, 0.1f }, { 0.0f, 0.0f, 1.0f }, triViewed, clipped[0], clipped[1]);
// We may end up with multiple triangles form the clip, so project as
// required
for (int n = 0; n < nClippedTriangles; n++)
{
// Project triangles from 3D --> 2D
triProjected.p[0] = Matrix_MultiplyVector(matProj, clipped[n].p[0]);
triProjected.p[1] = Matrix_MultiplyVector(matProj, clipped[n].p[1]);
triProjected.p[2] = Matrix_MultiplyVector(matProj, clipped[n].p[2]);
triProjected.col = clipped[n].col;
triProjected.t[0] = clipped[n].t[0];
triProjected.t[1] = clipped[n].t[1];
triProjected.t[2] = clipped[n].t[2];
triProjected.t[0].u = triProjected.t[0].u / triProjected.p[0].w;
triProjected.t[1].u = triProjected.t[1].u / triProjected.p[1].w;
triProjected.t[2].u = triProjected.t[2].u / triProjected.p[2].w;
triProjected.t[0].v = triProjected.t[0].v / triProjected.p[0].w;
triProjected.t[1].v = triProjected.t[1].v / triProjected.p[1].w;
triProjected.t[2].v = triProjected.t[2].v / triProjected.p[2].w;
triProjected.t[0].w = 1.0f / triProjected.p[0].w;
triProjected.t[1].w = 1.0f / triProjected.p[1].w;
triProjected.t[2].w = 1.0f / triProjected.p[2].w;
// Scale into view, we moved the normalising into cartesian space
// out of the matrix.vector function from the previous videos, so
// do this manually
triProjected.p[0] = Vector_Div(triProjected.p[0], triProjected.p[0].w);
triProjected.p[1] = Vector_Div(triProjected.p[1], triProjected.p[1].w);
triProjected.p[2] = Vector_Div(triProjected.p[2], triProjected.p[2].w);
// X/Y are inverted so put them back
triProjected.p[0].x *= -1.0f;
triProjected.p[1].x *= -1.0f;
triProjected.p[2].x *= -1.0f;
triProjected.p[0].y *= -1.0f;
triProjected.p[1].y *= -1.0f;
triProjected.p[2].y *= -1.0f;
// Offset verts into visible normalised space
vec3d vOffsetView = { 1,1,0 };
triProjected.p[0] = Vector_Add(triProjected.p[0], vOffsetView);
triProjected.p[1] = Vector_Add(triProjected.p[1], vOffsetView);
triProjected.p[2] = Vector_Add(triProjected.p[2], vOffsetView);
triProjected.p[0].x *= 0.5f * (float)ScreenWidth();
triProjected.p[0].y *= 0.5f * (float)ScreenHeight();
triProjected.p[1].x *= 0.5f * (float)ScreenWidth();
triProjected.p[1].y *= 0.5f * (float)ScreenHeight();
triProjected.p[2].x *= 0.5f * (float)ScreenWidth();
triProjected.p[2].y *= 0.5f * (float)ScreenHeight();
// Store triangle for sorting
vecTrianglesToRaster.push_back(triProjected);
}
}
}
// Sort triangles from back to front
/*sort(vecTrianglesToRaster.begin(), vecTrianglesToRaster.end(), [](triangle &t1, triangle &t2)
{
float z1 = (t1.p[0].z + t1.p[1].z + t1.p[2].z) / 3.0f;
float z2 = (t2.p[0].z + t2.p[1].z + t2.p[2].z) / 3.0f;
return z1 > z2;
});*/
// Clear Screen
Clear(olc::BLACK);
// Clear Depth Buffer
for (int i = 0; i < ScreenWidth()*ScreenHeight(); i++)
pDepthBuffer[i] = 0.0f;
// Loop through all transformed, viewed, projected, and sorted triangles
for (auto &triToRaster : vecTrianglesToRaster)
{
// Clip triangles against all four screen edges, this could yield
// a bunch of triangles, so create a queue that we traverse to
// ensure we only test new triangles generated against planes
triangle clipped[2];
list<triangle> listTriangles;
// Add initial triangle
listTriangles.push_back(triToRaster);
int nNewTriangles = 1;
for (int p = 0; p < 4; p++)
{
int nTrisToAdd = 0;
while (nNewTriangles > 0)
{
// Take triangle from front of queue
triangle test = listTriangles.front();
listTriangles.pop_front();
nNewTriangles--;
// Clip it against a plane. We only need to test each
// subsequent plane, against subsequent new triangles
// as all triangles after a plane clip are guaranteed
// to lie on the inside of the plane. I like how this
// comment is almost completely and utterly justified
switch (p)
{
case 0: nTrisToAdd = Triangle_ClipAgainstPlane({ 0.0f, 0.0f, 0.0f }, { 0.0f, 1.0f, 0.0f }, test, clipped[0], clipped[1]); break;
case 1: nTrisToAdd = Triangle_ClipAgainstPlane({ 0.0f, (float)ScreenHeight() - 1, 0.0f }, { 0.0f, -1.0f, 0.0f }, test, clipped[0], clipped[1]); break;
case 2: nTrisToAdd = Triangle_ClipAgainstPlane({ 0.0f, 0.0f, 0.0f }, { 1.0f, 0.0f, 0.0f }, test, clipped[0], clipped[1]); break;
case 3: nTrisToAdd = Triangle_ClipAgainstPlane({ (float)ScreenWidth() - 1, 0.0f, 0.0f }, { -1.0f, 0.0f, 0.0f }, test, clipped[0], clipped[1]); break;
}
// Clipping may yield a variable number of triangles, so
// add these new ones to the back of the queue for subsequent
// clipping against next planes
for (int w = 0; w < nTrisToAdd; w++)
listTriangles.push_back(clipped[w]);
}
nNewTriangles = listTriangles.size();
}
// Draw the transformed, viewed, clipped, projected, sorted, clipped triangles
for (auto &t : listTriangles)
{
#ifdef DO_TEXTURE_DEMO
TexturedTriangle(t.p[0].x, t.p[0].y, t.t[0].u, t.t[0].v, t.t[0].w,
t.p[1].x, t.p[1].y, t.t[1].u, t.t[1].v, t.t[1].w,
t.p[2].x, t.p[2].y, t.t[2].u, t.t[2].v, t.t[2].w, sprTex1);
#else
FillTriangle(t.p[0].x, t.p[0].y, t.p[1].x, t.p[1].y, t.p[2].x, t.p[2].y, t.col);
#endif
//DrawTriangle(t.p[0].x, t.p[0].y, t.p[1].x, t.p[1].y, t.p[2].x, t.p[2].y, olc::WHITE);
}
}
return true;
}
void TexturedTriangle( int x1, int y1, float u1, float v1, float w1,
int x2, int y2, float u2, float v2, float w2,
int x3, int y3, float u3, float v3, float w3,
olc::Sprite *tex)
{
if (y2 < y1)
{
swap(y1, y2);
swap(x1, x2);
swap(u1, u2);
swap(v1, v2);
swap(w1, w2);
}
if (y3 < y1)
{
swap(y1, y3);
swap(x1, x3);
swap(u1, u3);
swap(v1, v3);
swap(w1, w3);
}
if (y3 < y2)
{
swap(y2, y3);
swap(x2, x3);
swap(u2, u3);
swap(v2, v3);
swap(w2, w3);
}
int dy1 = y2 - y1;
int dx1 = x2 - x1;
float dv1 = v2 - v1;
float du1 = u2 - u1;
float dw1 = w2 - w1;
int dy2 = y3 - y1;
int dx2 = x3 - x1;
float dv2 = v3 - v1;
float du2 = u3 - u1;
float dw2 = w3 - w1;
float tex_u, tex_v, tex_w;
float dax_step = 0, dbx_step = 0,
du1_step = 0, dv1_step = 0,
du2_step = 0, dv2_step = 0,
dw1_step=0, dw2_step=0;
if (dy1) dax_step = dx1 / (float)abs(dy1);
if (dy2) dbx_step = dx2 / (float)abs(dy2);
if (dy1) du1_step = du1 / (float)abs(dy1);
if (dy1) dv1_step = dv1 / (float)abs(dy1);
if (dy1) dw1_step = dw1 / (float)abs(dy1);
if (dy2) du2_step = du2 / (float)abs(dy2);
if (dy2) dv2_step = dv2 / (float)abs(dy2);
if (dy2) dw2_step = dw2 / (float)abs(dy2);
if (dy1)
{
for (int i = y1; i <= y2; i++)
{
int ax = x1 + (float)(i - y1) * dax_step;
int bx = x1 + (float)(i - y1) * dbx_step;
float tex_su = u1 + (float)(i - y1) * du1_step;
float tex_sv = v1 + (float)(i - y1) * dv1_step;
float tex_sw = w1 + (float)(i - y1) * dw1_step;
float tex_eu = u1 + (float)(i - y1) * du2_step;
float tex_ev = v1 + (float)(i - y1) * dv2_step;
float tex_ew = w1 + (float)(i - y1) * dw2_step;
if (ax > bx)
{
swap(ax, bx);
swap(tex_su, tex_eu);
swap(tex_sv, tex_ev);
swap(tex_sw, tex_ew);
}
tex_u = tex_su;
tex_v = tex_sv;
tex_w = tex_sw;
float tstep = 1.0f / ((float)(bx - ax));
float t = 0.0f;
for (int j = ax; j < bx; j++)
{
tex_u = (1.0f - t) * tex_su + t * tex_eu;
tex_v = (1.0f - t) * tex_sv + t * tex_ev;
tex_w = (1.0f - t) * tex_sw + t * tex_ew;
if (tex_w > pDepthBuffer[i*ScreenWidth() + j])
{
Draw(j, i, tex->Sample(tex_u / tex_w, tex_v / tex_w));
pDepthBuffer[i*ScreenWidth() + j] = tex_w;
}
t += tstep;
}
}
}
dy1 = y3 - y2;
dx1 = x3 - x2;
dv1 = v3 - v2;
du1 = u3 - u2;
dw1 = w3 - w2;
if (dy1) dax_step = dx1 / (float)abs(dy1);
if (dy2) dbx_step = dx2 / (float)abs(dy2);
du1_step = 0, dv1_step = 0;
if (dy1) du1_step = du1 / (float)abs(dy1);
if (dy1) dv1_step = dv1 / (float)abs(dy1);
if (dy1) dw1_step = dw1 / (float)abs(dy1);
if (dy1)
{
for (int i = y2; i <= y3; i++)
{
int ax = x2 + (float)(i - y2) * dax_step;
int bx = x1 + (float)(i - y1) * dbx_step;
float tex_su = u2 + (float)(i - y2) * du1_step;
float tex_sv = v2 + (float)(i - y2) * dv1_step;
float tex_sw = w2 + (float)(i - y2) * dw1_step;
float tex_eu = u1 + (float)(i - y1) * du2_step;
float tex_ev = v1 + (float)(i - y1) * dv2_step;
float tex_ew = w1 + (float)(i - y1) * dw2_step;
if (ax > bx)
{
swap(ax, bx);
swap(tex_su, tex_eu);
swap(tex_sv, tex_ev);
swap(tex_sw, tex_ew);
}
tex_u = tex_su;
tex_v = tex_sv;
tex_w = tex_sw;
float tstep = 1.0f / ((float)(bx - ax));
float t = 0.0f;
for (int j = ax; j < bx; j++)
{
tex_u = (1.0f - t) * tex_su + t * tex_eu;
tex_v = (1.0f - t) * tex_sv + t * tex_ev;
tex_w = (1.0f - t) * tex_sw + t * tex_ew;
if (tex_w > pDepthBuffer[i*ScreenWidth() + j])
{
Draw(j, i, tex->Sample(tex_u / tex_w, tex_v / tex_w));
pDepthBuffer[i*ScreenWidth() + j] = tex_w;
}
t += tstep;
}
}
}
}
};
int main()
{
olcEngine3D demo;
if (demo.Construct(512, 480, 2, 2))
demo.Start();
return 0;
}