*背面剔除

1 files changed, 24 insertions, 10 deletions

diff --git a/src/core/device.c b/src/core/device.c
index f5ed4eb..ad640c6 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -172,12 +172,19 @@ bool ssr_isenable(uint mask) {
 void ssr_viewport(float l, float r, float b, float t) {
 }
 
+void ssr_ortho(float l, float r, float b, float t, float n, float f) {
+	Mat4 m;
+	mat4_setortho(l, r, b, t, n, f, &m);
+	mat4_multiply(&MATRIX, &m, &MATRIX);
+}
+
 void ssr_frustum(float l, float r, float b, float t, float n, float f) {
 	Mat4 m;
 	mat4_setfrustum(l, r, b, t, n, f, &m);
 	mat4_multiply(&MATRIX, &m, &MATRIX);
 }
 
+/*ע������nf��Ҫ����������������*/
 void ssr_perspective(float fov, float aspect, float n, float f) {
 	Mat4 m;
 	mat4_setperspective(fov, aspect, n, f, &m);
@@ -232,9 +239,11 @@ bool ssr_testdepthf(uint x, uint y, float depth) {
 
 void ssrU_viewport(Vec2* p, Vec2* out) {
 	ssr_assert(p && out);
-	int halfw = config.width >> 1, halfh = config.height >> 1;
-	out->x = p->x * halfw + halfw + 0.5f;
-	out->y = halfh - p->y * halfh + 0.5f;
+	float halfw = config.width / 2.f, halfh = config.height / 2.f;
+	out->x = (int)(p->x * halfw + halfw);
+	out->y = (int)(halfh - p->y * halfh);
+	//out->x = (int)((p->x + 1) * (halfw - 0.5f));
+	//out->y = (int)((1 - p->y) * (halfh - 0.5f));
 }
 
 void ssr_bindvertices(Vert** verts, int nverts, uint* indices, int nprims) {
@@ -254,8 +263,8 @@ void ssr_unuseprogram() {
 	state.program = NULL;
 }
 
-static Vec4* homos = 0;
-static uint tri[3]; /*�������������������*/
+static Vec4* homos = NULL;
+static uint tri[3];
 static Vec3 ab, ac;
 static Mat4 mvp, mv;
 void ssr_draw(ssr_PrimitiveType primitive) {
@@ -285,14 +294,19 @@ void ssr_draw(ssr_PrimitiveType primitive) {
 			tri[2] = state.indices[i * 3 + 2];
 
 			/* back face culling */
-			if (ssr_isenable(ENABLEMASK_BACKFACECULL)) {
-				vec3_minus(&homos[tri[1]], &homos[tri[0]], &ab);
-				vec3_minus(&homos[tri[2]], &homos[tri[0]], &ac);
-				if (ab.x * ac.y - ab.y * ac.x <= 0) { 
-					continue; 
+			if (ssr_isenable(ENABLEMASK_BACKFACECULL)) { 
+				float w0 = 1 / homos[tri[0]].w, w1 = 1 / homos[tri[1]].w, w2 = 1 / homos[tri[2]].w;
+				Vec2* h0 = &homos[tri[0]], *h1 = &homos[tri[1]], *h2 = &homos[tri[2]];
+				ab.x = h1->x * w1 - h0->x * w0; /*����Ļ�ռ��������޳�*/
+				ab.y = h1->y * w1 - h0->y * w0;
+				ac.x = h2->x * w2 - h0->x * w0;
+				ac.y = h2->y * w2 - h0->y * w0;
+				if (ab.x * ac.y - ab.y * ac.x <= 0) {
+					continue;
 				}
 			}
 
+			/* render triangle */
 			ssrR_triangle(
 				&homos[tri[0]],
 				&homos[tri[1]],