* Adjustment: Initial CMake reworking.

Engine/lib/bullet/examples/TinyRenderer/our_gl.cpp

@@ -0,0 +1,117 @@
+#include <cmath>
+#include <limits>
+#include <cstdlib>
+#include "our_gl.h"
+#include "Bullet3Common/b3MinMax.h"
+
+
+
+
+IShader::~IShader() {}
+
+Matrix viewport(int x, int y, int w, int h) 
+{
+    Matrix Viewport;
+    Viewport = Matrix::identity();
+    Viewport[0][3] = x+w/2.f;
+    Viewport[1][3] = y+h/2.f;
+    Viewport[2][3] = 1.f;
+    Viewport[0][0] = w/2.f;
+    Viewport[1][1] = h/2.f;
+    Viewport[2][2] = 0;
+    return Viewport;
+}
+
+Matrix projection(float coeff) {
+    Matrix Projection;
+    Projection = Matrix::identity();
+    Projection[3][2] = coeff;
+    return Projection;
+}
+
+Matrix lookat(Vec3f eye, Vec3f center, Vec3f up) {
+    Vec3f z = (eye-center).normalize();
+    Vec3f x = cross(up,z).normalize();
+    Vec3f y = cross(z,x).normalize();
+    Matrix Minv = Matrix::identity();
+    Matrix Tr   = Matrix::identity();
+    for (int i=0; i<3; i++) {
+        Minv[0][i] = x[i];
+        Minv[1][i] = y[i];
+        Minv[2][i] = z[i];
+        Tr[i][3] = -center[i];
+    }
+    Matrix ModelView;
+    ModelView = Minv*Tr;
+    return ModelView;
+}
+
+Vec3f barycentric(Vec2f A, Vec2f B, Vec2f C, Vec2f P) {
+    Vec3f s[2];
+    for (int i=2; i--; ) {
+        s[i][0] = C[i]-A[i];
+        s[i][1] = B[i]-A[i];
+        s[i][2] = A[i]-P[i];
+    }
+    Vec3f u = cross(s[0], s[1]);
+    if (std::abs(u[2])>1e-2) // dont forget that u[2] is integer. If it is zero then triangle ABC is degenerate
+        return Vec3f(1.f-(u.x+u.y)/u.z, u.y/u.z, u.x/u.z);
+    return Vec3f(-1,1,1); // in this case generate negative coordinates, it will be thrown away by the rasterizator
+}
+
+void triangle(mat<4,3,float> &clipc, IShader &shader, TGAImage &image, float *zbuffer, const Matrix& viewPortMatrix) 
+{
+    triangle(clipc,shader,image,zbuffer,0,viewPortMatrix,0);
+}
+
+void triangle(mat<4,3,float> &clipc, IShader &shader, TGAImage &image, float *zbuffer, int* segmentationMaskBuffer, const Matrix& viewPortMatrix, int objectIndex) {
+	mat<3,4,float> pts  = (viewPortMatrix*clipc).transpose(); // transposed to ease access to each of the points
+	
+	
+	//we don't clip triangles that cross the near plane, just discard them instead of showing artifacts
+	if (pts[0][3]<0 || pts[1][3] <0 || pts[2][3] <0)
+		return;
+
+	
+	mat<3,2,float> pts2;
+    for (int i=0; i<3; i++) pts2[i] = proj<2>(pts[i]/pts[i][3]);
+
+    Vec2f bboxmin( std::numeric_limits<float>::max(),  std::numeric_limits<float>::max());
+    Vec2f bboxmax(-std::numeric_limits<float>::max(), -std::numeric_limits<float>::max());
+    Vec2f clamp(image.get_width()-1, image.get_height()-1);
+	
+    for (int i=0; i<3; i++) {
+        for (int j=0; j<2; j++) {
+            bboxmin[j] = b3Max(0.f,      b3Min(bboxmin[j], pts2[i][j]));
+            bboxmax[j] = b3Min(clamp[j], b3Max(bboxmax[j], pts2[i][j]));
+        }
+    }
+
+	
+	
+	Vec2i P;
+    TGAColor color;
+    for (P.x=bboxmin.x; P.x<=bboxmax.x; P.x++) {
+        for (P.y=bboxmin.y; P.y<=bboxmax.y; P.y++) {
+            Vec3f bc_screen  = barycentric(pts2[0], pts2[1], pts2[2], P);
+
+			
+            Vec3f bc_clip    = Vec3f(bc_screen.x/pts[0][3], bc_screen.y/pts[1][3], bc_screen.z/pts[2][3]);
+            bc_clip = bc_clip/(bc_clip.x+bc_clip.y+bc_clip.z);
+            float frag_depth = -1*(clipc[2]*bc_clip);
+            if (bc_screen.x<0 || bc_screen.y<0 || bc_screen.z<0 || 
+				zbuffer[P.x+P.y*image.get_width()]>frag_depth) 
+				continue;
+            bool discard = shader.fragment(bc_clip, color);
+            if (!discard) {
+                zbuffer[P.x+P.y*image.get_width()] = frag_depth;
+                if (segmentationMaskBuffer)
+                {
+                    segmentationMaskBuffer[P.x+P.y*image.get_width()] = objectIndex;
+                }
+                image.set(P.x, P.y, color);
+            }
+        }
+    }
+}
+