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gl-clip-arrays.c
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/* KallistiGL for KallistiOS ##version##
libgl/gl-clip.c
Copyright (C) 2013-2014 Josh Pearson
Near-Z Clipping Algorithm (C) 2013-2014 Josh PH3NOM Pearson
Input Primitive Types Supported:
-GL_TRIANGLES
-GL_TRIANGLE_STRIPS
-GL_QUADS
Outputs a mix of Triangles and Triangle Strips for use with the PVR
*/
#include <stdio.h>
#include <string.h>
#include "gl.h"
#include "gl-api.h"
#include "gl-clip.h"
static inline void _glKosVertexClipZNear2(pvr_vertex_t *v1, pvr_vertex_t *v2,
GLfloat *w1, GLfloat *w2,
glTexCoord *uva, glTexCoord *uvb) {
GLfloat MAG = ((CLIP_NEARZ - v1->z) / (v2->z - v1->z));
colorui *c1 = (colorui *)&v1->argb; /* GLubyte Color Component Pointer */
colorui *c2 = (colorui *)&v2->argb;
v1->x += (v2->x - v1->x) * MAG; /* Clip Vertex X, Y, Z Components */
v1->y += (v2->y - v1->y) * MAG;
v1->z += (v2->z - v1->z) * MAG;
v1->u += (v2->u - v1->u) * MAG; /* Clip Vertex Texture Coordinates */
v1->v += (v2->v - v1->v) * MAG;
c1->a += (c2->a - c1->a) * MAG; /* Clip Vertex Color per ARGB component */
c1->r += (c2->r - c1->r) * MAG;
c1->g += (c2->g - c1->g) * MAG;
c1->b += (c2->b - c1->b) * MAG;
*w1 += (*w2 - *w1) * MAG; /* Clip Vertex W Component */
uva->u += (uvb->u - uva->u) * MAG; /* Clip Vertex Multi-Texture Coordinates */
uva->v += (uvb->v - uva->v) * MAG;
}
static inline void _glKosVertexClipZNear3(pvr_vertex_t *v1, pvr_vertex_t *v2, float *w1, float *w2) {
GLfloat MAG = ((CLIP_NEARZ - v1->z) / (v2->z - v1->z));
colorui *c1 = (colorui *)&v1->argb;
colorui *c2 = (colorui *)&v2->argb;
v1->x += (v2->x - v1->x) * MAG;
v1->y += (v2->y - v1->y) * MAG;
v1->z += (v2->z - v1->z) * MAG;
v1->u += (v2->u - v1->u) * MAG;
v1->v += (v2->v - v1->v) * MAG;
c1->a += (c2->a - c1->a) * MAG;
c1->r += (c2->r - c1->r) * MAG;
c1->g += (c2->g - c1->g) * MAG;
c1->b += (c2->b - c1->b) * MAG;
*w1 += (*w2 - *w1) * MAG;
}
static inline void _glKosVertexPerspectiveDivide(pvr_vertex_t *dst, GLfloat w) {
dst->z = 1.0f / w;
dst->x *= dst->z;
dst->y *= dst->z;
}
static inline GLubyte _glKosClipTriTransformed(pvr_vertex_t *src, GLfloat *w, pvr_vertex_t *dst) {
GLushort clip = 0; /* Clip Code for current Triangle */
GLubyte verts_in = 0; /* # of Vertices inside clip plane for current Triangle */
GLfloat W[4] = { w[0], w[1], w[2] }; /* W Component for Perspective Divide */
(src[0].z >= CLIP_NEARZ) ? clip |= FIRST : ++verts_in;
(src[1].z >= CLIP_NEARZ) ? clip |= SECOND : ++verts_in;
(src[2].z >= CLIP_NEARZ) ? clip |= THIRD : ++verts_in;
switch(verts_in) { /* Start by examining # of vertices inside clip plane */
case 0: /* All Vertices of Triangle are Outside of clip plne */
return 0;
case 3: /* All Vertices of Triangle are inside of clip plne */
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
dst[0].flags = dst[1].flags = PVR_CMD_VERTEX;
dst[2].flags = PVR_CMD_VERTEX_EOL;
return 3;
case 1:/* 1 Vertex of Triangle is inside of clip plane = output 1 Triangle */
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
switch(clip) {
case FIRST_TWO_OUT:
_glKosVertexClipZNear3(&dst[0], &dst[2], &W[0], &W[2]);
_glKosVertexClipZNear3(&dst[1], &dst[2], &W[1], &W[2]);
break;
case FIRST_AND_LAST_OUT:
_glKosVertexClipZNear3(&dst[0], &dst[1], &W[0], &W[1]);
_glKosVertexClipZNear3(&dst[2], &dst[1], &W[2], &W[1]);
break;
case LAST_TWO_OUT:
_glKosVertexClipZNear3(&dst[1], &dst[0], &W[1], &W[0]);
_glKosVertexClipZNear3(&dst[2], &dst[0], &W[2], &W[0]);
break;
}
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
dst[0].flags = dst[1].flags = PVR_CMD_VERTEX;
dst[2].flags = PVR_CMD_VERTEX_EOL;
return 3;
case 2:/* 2 Vertices of Triangle are inside of clip plane = output 2 Triangles */
switch(clip) {
case FIRST:
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[0], &dst[2]);
_glKosVertexCopyPVR(&src[2], &dst[3]);
W[3] = W[2];
W[2] = W[0];
break;
case SECOND:
_glKosVertexCopyPVR(&src[1], &dst[0]);
_glKosVertexCopyPVR(&src[2], &dst[1]);
_glKosVertexCopyPVR(&src[1], &dst[2]);
_glKosVertexCopyPVR(&src[0], &dst[3]);
W[3] = W[0];
W[0] = W[1];
W[1] = W[2];
W[2] = W[0];
break;
case THIRD:
_glKosVertexCopyPVR(&src[2], &dst[0]);
_glKosVertexCopyPVR(&src[0], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
_glKosVertexCopyPVR(&src[1], &dst[3]);
W[3] = W[1];
W[1] = W[0];
W[0] = W[2];
break;
}
_glKosVertexClipZNear3(&dst[0], &dst[1], &W[0], &W[1]);
_glKosVertexClipZNear3(&dst[2], &dst[3], &W[2], &W[3]);
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
_glKosVertexPerspectiveDivide(&dst[3], W[3]);
dst[0].flags = dst[1].flags = dst[2].flags = PVR_CMD_VERTEX;
dst[3].flags = PVR_CMD_VERTEX_EOL;
return 4;
}
return 0;
}
GLuint _glKosClipTrianglesTransformed(pvr_vertex_t *src, GLfloat *w, pvr_vertex_t *dst, GLuint count) {
GLuint verts_out = 0;
GLuint i;
for(i = 0; i < count; i += 3)
verts_out += _glKosClipTriTransformed(&src[i], &w[i], &dst[verts_out]);
return verts_out;
}
GLuint _glKosClipTriangleStripTransformed(pvr_vertex_t *src, GLfloat *w, pvr_vertex_t *dst, GLuint count) {
GLuint verts_out = 0;
GLuint i;
for(i = 0; i < (count - 2); i ++)
verts_out += _glKosClipTriTransformed(&src[i], &w[i], &dst[verts_out]);
return verts_out;
}
unsigned int _glKosClipQuadsTransformed(pvr_vertex_t *src, GLfloat *w, pvr_vertex_t *dst, GLuint count) {
GLuint i, verts_out = 0;
pvr_vertex_t qv[3];
GLfloat W[3];
for(i = 0; i < count; i += 4) { /* Iterate all Quads, Rearranging into Triangle Strips */
_glKosVertexCopyPVR(&src[i + 0], &qv[0]);
_glKosVertexCopyPVR(&src[i + 2], &qv[1]);
_glKosVertexCopyPVR(&src[i + 3], &qv[2]);
W[0] = w[0];
W[1] = w[2];
W[2] = w[3];
verts_out += _glKosClipTriTransformed(&src[i], &w[i], &dst[verts_out]);
verts_out += _glKosClipTriTransformed(qv, W, &dst[verts_out]);
}
return verts_out;
}
static inline GLubyte _glKosClipTriTransformedMT(pvr_vertex_t *src, float *w, pvr_vertex_t *dst,
GLfloat *uvsrc, glTexCoord *uvdst, GLuint uv_src_stride) {
GLushort clip = 0; /* Clip Code for current Triangle */
GLubyte verts_in = 0; /* # of Vertices inside clip plane for current Triangle */
GLfloat W[4] = { w[0], w[1], w[2] }; /* W Component for Perspective Divide */
(src[0].z >= CLIP_NEARZ) ? clip |= FIRST : ++verts_in;
(src[1].z >= CLIP_NEARZ) ? clip |= SECOND : ++verts_in;
(src[2].z >= CLIP_NEARZ) ? clip |= THIRD : ++verts_in;
switch(verts_in) { /* Start by examining # of vertices inside clip plane */
case 0: /* All Vertices of Triangle are Outside of clip plane */
return 0;
case 3: /* All Vertices of Triangle are Inside of clip plane */
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[2]);
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
dst[0].flags = dst[1].flags = PVR_CMD_VERTEX;
dst[2].flags = PVR_CMD_VERTEX_EOL;
return 3;
case 1:/* 1 Vertex of Triangle is Inside of clip plane = output 1 Triangle */
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[2]);
switch(clip) {
case FIRST_TWO_OUT:
_glKosVertexClipZNear2(&dst[0], &dst[2], &W[0], &W[2], &uvdst[0], &uvdst[2]);
_glKosVertexClipZNear2(&dst[1], &dst[2], &W[1], &W[2], &uvdst[1], &uvdst[2]);
break;
case FIRST_AND_LAST_OUT:
_glKosVertexClipZNear2(&dst[0], &dst[1], &W[0], &W[1], &uvdst[0], &uvdst[1]);
_glKosVertexClipZNear2(&dst[2], &dst[1], &W[2], &W[1], &uvdst[2], &uvdst[1]);
break;
case LAST_TWO_OUT:
_glKosVertexClipZNear2(&dst[1], &dst[0], &W[1], &W[0], &uvdst[1], &uvdst[0]);
_glKosVertexClipZNear2(&dst[2], &dst[0], &W[2], &W[0], &uvdst[2], &uvdst[0]);
break;
}
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
dst[0].flags = dst[1].flags = PVR_CMD_VERTEX;
dst[2].flags = PVR_CMD_VERTEX_EOL;
return 3;
case 2:/* 2 Vertices of Triangle are inside of clip plane = output 2 Triangles */
switch(clip) {
case FIRST:
_glKosVertexCopyPVR(&src[0], &dst[0]);
_glKosVertexCopyPVR(&src[1], &dst[1]);
_glKosVertexCopyPVR(&src[0], &dst[2]);
_glKosVertexCopyPVR(&src[2], &dst[3]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[3]);
W[3] = W[2];
W[2] = W[0];
break;
case SECOND:
_glKosVertexCopyPVR(&src[1], &dst[0]);
_glKosVertexCopyPVR(&src[2], &dst[1]);
_glKosVertexCopyPVR(&src[1], &dst[2]);
_glKosVertexCopyPVR(&src[0], &dst[3]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[3]);
W[3] = W[0];
W[0] = W[1];
W[1] = W[2];
W[2] = W[0];
break;
case THIRD:
_glKosVertexCopyPVR(&src[2], &dst[0]);
_glKosVertexCopyPVR(&src[0], &dst[1]);
_glKosVertexCopyPVR(&src[2], &dst[2]);
_glKosVertexCopyPVR(&src[1], &dst[3]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[0], &uvdst[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride + uv_src_stride], &uvdst[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[uv_src_stride], &uvdst[3]);
W[3] = W[1];
W[1] = W[0];
W[0] = W[2];
break;
}
_glKosVertexClipZNear2(&dst[0], &dst[1], &W[0], &W[1], &uvdst[0], &uvdst[1]);
_glKosVertexClipZNear2(&dst[2], &dst[3], &W[2], &W[3], &uvdst[2], &uvdst[3]);
_glKosVertexPerspectiveDivide(&dst[0], W[0]);
_glKosVertexPerspectiveDivide(&dst[1], W[1]);
_glKosVertexPerspectiveDivide(&dst[2], W[2]);
_glKosVertexPerspectiveDivide(&dst[3], W[3]);
dst[0].flags = dst[1].flags = dst[2].flags = PVR_CMD_VERTEX;
dst[3].flags = PVR_CMD_VERTEX_EOL;
return 4;
}
return 0;
}
GLuint _glKosClipTrianglesTransformedMT(pvr_vertex_t *src, float *w, pvr_vertex_t *dst,
GLfloat *uvsrc, glTexCoord *uvdst, GLuint uv_src_stride,
GLuint count) {
GLuint verts_out = 0;
GLuint i;
for(i = 0; i < count; i += 3)
verts_out += _glKosClipTriTransformedMT(&src[i], &w[i], &dst[verts_out],
&uvsrc[i * uv_src_stride], &uvdst[verts_out], uv_src_stride);
return verts_out;
}
GLuint _glKosClipTriangleStripTransformedMT(pvr_vertex_t *src, float *w, pvr_vertex_t *dst,
GLfloat *uvsrc, glTexCoord *uvdst, GLuint uv_src_stride, GLuint count) {
GLuint verts_out = 0;
GLuint i;
for(i = 0; i < (count - 2); i ++)
verts_out += _glKosClipTriTransformedMT(&src[i], &w[i], &dst[verts_out],
&uvsrc[i * uv_src_stride], &uvdst[verts_out], uv_src_stride);
return verts_out;
}
GLuint _glKosClipQuadsTransformedMT(pvr_vertex_t *src, float *w, pvr_vertex_t *dst,
GLfloat *uvsrc, glTexCoord *uvdst, GLuint uv_src_stride, GLuint count) {
GLuint i, verts_out = 0;
pvr_vertex_t qv[3];
glTexCoord uv[3];
GLfloat W[3];
for(i = 0; i < count; i += 4) {
_glKosVertexCopyPVR(&src[i + 0], &qv[0]);
_glKosVertexCopyPVR(&src[i + 2], &qv[1]);
_glKosVertexCopyPVR(&src[i + 3], &qv[2]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[i * uv_src_stride], &uv[0]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[i * uv_src_stride + (uv_src_stride * 2)], &uv[1]);
_glKosTexCoordCopy((glTexCoord *)&uvsrc[i * uv_src_stride + (uv_src_stride * 3)], &uv[2]);
W[0] = w[0];
W[1] = w[2];
W[2] = w[3];
verts_out += _glKosClipTriTransformedMT(&src[i], &w[i], &dst[verts_out],
&uvsrc[i * uv_src_stride], &uvdst[verts_out], uv_src_stride);
verts_out += _glKosClipTriTransformedMT(qv, W, &dst[verts_out],
(GLfloat *)uv, &uvdst[verts_out], 2);
}
return verts_out;
}