mirror of
https://github.com/bulletphysics/bullet3
synced 2024-12-14 22:00:05 +00:00
199 lines
6.6 KiB
C++
199 lines
6.6 KiB
C++
#include <cmath>
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#include <limits>
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#include <cstdlib>
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#include "our_gl.h"
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#include "Bullet3Common/b3MinMax.h"
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IShader::~IShader() {}
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Matrix viewport(int x, int y, int w, int h)
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{
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Matrix Viewport;
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Viewport = Matrix::identity();
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Viewport[0][3] = x+w/2.f;
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Viewport[1][3] = y+h/2.f;
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Viewport[2][3] = .5f;
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Viewport[0][0] = w/2.f;
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Viewport[1][1] = h/2.f;
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Viewport[2][2] = .5f;
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return Viewport;
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}
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Matrix projection(float coeff) {
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Matrix Projection;
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Projection = Matrix::identity();
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Projection[3][2] = coeff;
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return Projection;
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}
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Matrix lookat(Vec3f eye, Vec3f center, Vec3f up) {
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Vec3f f = (center - eye).normalize();
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Vec3f u = up.normalize();
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Vec3f s = cross(f,u).normalize();
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u = cross(s,f);
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Matrix ModelView;
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ModelView[0][0] = s.x;
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ModelView[0][1] = s.y;
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ModelView[0][2] = s.z;
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ModelView[1][0] = u.x;
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ModelView[1][1] = u.y;
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ModelView[1][2] = u.z;
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ModelView[2][0] =-f.x;
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ModelView[2][1] =-f.y;
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ModelView[2][2] =-f.z;
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ModelView[3][0] = 0.f;
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ModelView[3][1] = 0.f;
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ModelView[3][2] = 0.f;
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ModelView[0][3] = -(s[0]*eye[0]+s[1]*eye[1]+s[2]*eye[2]);
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ModelView[1][3] = -(u[0]*eye[0]+u[1]*eye[1]+u[2]*eye[2]);
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ModelView[2][3] = f[0]*eye[0]+f[1]*eye[1]+f[2]*eye[2];
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ModelView[3][3] = 1.f;
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return ModelView;
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}
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Vec3f barycentric(Vec2f A, Vec2f B, Vec2f C, Vec2f P) {
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Vec3f s[2];
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for (int i=2; i--; ) {
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s[i][0] = C[i]-A[i];
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s[i][1] = B[i]-A[i];
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s[i][2] = A[i]-P[i];
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}
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Vec3f u = cross(s[0], s[1]);
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if (std::abs(u[2])>1e-2) // dont forget that u[2] is integer. If it is zero then triangle ABC is degenerate
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return Vec3f(1.f-(u.x+u.y)/u.z, u.y/u.z, u.x/u.z);
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return Vec3f(-1,1,1); // in this case generate negative coordinates, it will be thrown away by the rasterizator
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}
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void triangleClipped(mat<4,3,float> &clipc, mat<4,3,float> &orgClipc, IShader &shader, TGAImage &image, float *zbuffer, const Matrix& viewPortMatrix)
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{
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triangleClipped(clipc, orgClipc,shader,image,zbuffer,0,viewPortMatrix,0);
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}
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void triangleClipped(mat<4,3,float> &clipc, mat<4,3,float> &orgClipc, IShader &shader, TGAImage &image, float *zbuffer, int* segmentationMaskBuffer, const Matrix& viewPortMatrix, int objectAndLinkIndex)
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{
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mat<3,4,float> screenSpacePts = (viewPortMatrix*clipc).transpose(); // transposed to ease access to each of the points
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mat<3,2,float> pts2;
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for (int i=0; i<3; i++)
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{
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pts2[i] = proj<2>(screenSpacePts[i]/screenSpacePts[i][3]);
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}
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Vec2f bboxmin( std::numeric_limits<float>::max(), std::numeric_limits<float>::max());
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Vec2f bboxmax(-std::numeric_limits<float>::max(), -std::numeric_limits<float>::max());
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Vec2f clamp(image.get_width()-1, image.get_height()-1);
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for (int i=0; i<3; i++) {
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for (int j=0; j<2; j++) {
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bboxmin[j] = b3Max(0.f, b3Min(bboxmin[j], pts2[i][j]));
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bboxmax[j] = b3Min(clamp[j], b3Max(bboxmax[j], pts2[i][j]));
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}
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}
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Vec2i P;
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TGAColor color;
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mat<3,4,float> orgScreenSpacePts = (viewPortMatrix*orgClipc).transpose(); // transposed to ease access to each of the points
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mat<3,2,float> orgPts2;
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for (int i=0; i<3; i++)
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{
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orgPts2[i] = proj<2>(orgScreenSpacePts[i]/orgScreenSpacePts[i][3]);
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}
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for (P.x=bboxmin.x; P.x<=bboxmax.x; P.x++) {
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for (P.y=bboxmin.y; P.y<=bboxmax.y; P.y++)
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{
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float frag_depth = 0;
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{
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Vec3f bc_screen = barycentric(pts2[0], pts2[1], pts2[2], P);
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Vec3f bc_clip = Vec3f(bc_screen.x/screenSpacePts[0][3], bc_screen.y/screenSpacePts[1][3], bc_screen.z/screenSpacePts[2][3]);
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bc_clip = bc_clip/(bc_clip.x+bc_clip.y+bc_clip.z);
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frag_depth = -1*(clipc[2]*bc_clip);
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if (bc_screen.x<0 || bc_screen.y<0 || bc_screen.z<0 ||
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zbuffer[P.x+P.y*image.get_width()]>frag_depth)
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continue;
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}
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Vec3f bc_screen2 = barycentric(orgPts2[0], orgPts2[1], orgPts2[2], P);
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Vec3f bc_clip2 = Vec3f(bc_screen2.x/orgScreenSpacePts[0][3], bc_screen2.y/orgScreenSpacePts[1][3], bc_screen2.z/orgScreenSpacePts[2][3]);
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bc_clip2 = bc_clip2/(bc_clip2.x+bc_clip2.y+bc_clip2.z);
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float frag_depth2 = -1*(orgClipc[2]*bc_clip2);
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bool discard = shader.fragment(bc_clip2, color);
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if (!discard) {
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zbuffer[P.x+P.y*image.get_width()] = frag_depth;
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if (segmentationMaskBuffer)
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{
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segmentationMaskBuffer[P.x+P.y*image.get_width()] = objectAndLinkIndex;
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}
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image.set(P.x, P.y, color);
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}
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}
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}
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}
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void triangle(mat<4,3,float> &clipc, IShader &shader, TGAImage &image, float *zbuffer, const Matrix& viewPortMatrix)
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{
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triangle(clipc,shader,image,zbuffer,0,viewPortMatrix,0);
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}
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void triangle(mat<4,3,float> &clipc, IShader &shader, TGAImage &image, float *zbuffer, int* segmentationMaskBuffer, const Matrix& viewPortMatrix, int objectAndLinkIndex) {
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mat<3,4,float> pts = (viewPortMatrix*clipc).transpose(); // transposed to ease access to each of the points
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mat<3,2,float> pts2;
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for (int i=0; i<3; i++) pts2[i] = proj<2>(pts[i]/pts[i][3]);
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Vec2f bboxmin( std::numeric_limits<float>::max(), std::numeric_limits<float>::max());
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Vec2f bboxmax(-std::numeric_limits<float>::max(), -std::numeric_limits<float>::max());
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Vec2f clamp(image.get_width()-1, image.get_height()-1);
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for (int i=0; i<3; i++) {
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for (int j=0; j<2; j++) {
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bboxmin[j] = b3Max(0.f, b3Min(bboxmin[j], pts2[i][j]));
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bboxmax[j] = b3Min(clamp[j], b3Max(bboxmax[j], pts2[i][j]));
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}
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}
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Vec2i P;
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TGAColor color;
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for (P.x=bboxmin.x; P.x<=bboxmax.x; P.x++) {
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for (P.y=bboxmin.y; P.y<=bboxmax.y; P.y++) {
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Vec3f bc_screen = barycentric(pts2[0], pts2[1], pts2[2], P);
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Vec3f bc_clip = Vec3f(bc_screen.x/pts[0][3], bc_screen.y/pts[1][3], bc_screen.z/pts[2][3]);
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bc_clip = bc_clip/(bc_clip.x+bc_clip.y+bc_clip.z);
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float frag_depth = -1*(clipc[2]*bc_clip);
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if (bc_screen.x<0 || bc_screen.y<0 || bc_screen.z<0 ||
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zbuffer[P.x+P.y*image.get_width()]>frag_depth)
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continue;
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bool discard = shader.fragment(bc_clip, color);
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if (frag_depth<-shader.m_farPlane)
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discard=true;
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if (frag_depth>shader.m_nearPlane)
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discard=true;
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if (!discard) {
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zbuffer[P.x+P.y*image.get_width()] = frag_depth;
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if (segmentationMaskBuffer)
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{
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segmentationMaskBuffer[P.x+P.y*image.get_width()] = objectAndLinkIndex;
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}
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image.set(P.x, P.y, color);
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}
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}
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}
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}
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