311 lines
11 KiB
C
311 lines
11 KiB
C
/* KallistiGL for KallistiOS ##version##
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libgl/gl-clip.c
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Copyright (C) 2013-2014 Josh Pearson
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Near-Z Clipping Algorithm (C) 2013-2014 Josh PH3NOM Pearson
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Input Primitive Types Supported:
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-GL_TRIANGLES
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-GL_TRIANGLE_STRIPS
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-GL_QUADS
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Outputs a mix of Triangles and Triangle Strips for use with the PVR
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*/
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#include <stdio.h>
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#include <string.h>
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#include "gl.h"
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#include "gl-api.h"
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#include "gl-clip.h"
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static float3 CLIP_BUF[1024 * 32];
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static inline void _glKosVertexClipZNear(pvr_vertex_t *v1, pvr_vertex_t *v2, float MAG) {
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colorui *c1 = (colorui *)&v1->argb;
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colorui *c2 = (colorui *)&v2->argb;
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v1->x += (v2->x - v1->x) * MAG;
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v1->y += (v2->y - v1->y) * MAG;
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v1->z += (v2->z - v1->z) * MAG;
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v1->u += (v2->u - v1->u) * MAG;
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v1->v += (v2->v - v1->v) * MAG;
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c1->a += (c2->a - c1->a) * MAG;
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c1->r += (c2->r - c1->r) * MAG;
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c1->g += (c2->g - c1->g) * MAG;
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c1->b += (c2->b - c1->b) * MAG;
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}
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static GLuint _glKosTransformClip(pvr_vertex_t *v, GLint count) {
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pvr_vertex_t *V = v;
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float3 *C = CLIP_BUF;
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GLuint in = 0;
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while(count--) {
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mat_trans_single3_nodiv_nomod(V->x, V->y, V->z, C->x, C->y, C->z);
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if(C->z < CLIP_NEARZ) ++in;
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++C;
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++V;
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}
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return in;
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}
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GLuint _glKosClipTriangleStrip(pvr_vertex_t *src, pvr_vertex_t *dst, GLuint vertices) {
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GLuint i, v = 0, in = _glKosTransformClip(src, vertices);
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float3 *C = CLIP_BUF;
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if(in == vertices) {
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memcpy(dst, src, vertices * 0x20);
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pvr_vertex_t *v = dst;
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while(--in) {
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v->flags = PVR_CMD_VERTEX;
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++v;
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}
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v->flags = PVR_CMD_VERTEX_EOL;
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return vertices;
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}
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else if(in == 0)
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return 0;
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/* Iterate all Triangles of the Strip - Hence looping vertices-2 times */
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for(i = 0; i < ((vertices) - 2); i++) {
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GLushort clip = 0; /* Clip Code for current Triangle */
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GLubyte verts_in = 0; /* # of Verteices inside clip plane for current Triangle */
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C->z >= CLIP_NEARZ ? clip |= FIRST : ++verts_in;
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(C + 1)->z >= CLIP_NEARZ ? clip |= SECOND : ++verts_in;
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(C + 2)->z >= CLIP_NEARZ ? clip |= THIRD : ++verts_in;
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switch(verts_in) { /* Start by examining # of vertices inside clip plane */
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case 0: /* All Vertices of Triangle are outside of clip plne */
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break;
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case 3: /* All Vertices of Triangle are inside of clip plne */
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memcpy(&dst[v], &src[i], 96);
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dst[v].flags = dst[v + 1].flags = PVR_CMD_VERTEX;
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dst[v + 2].flags = PVR_CMD_VERTEX_EOL;
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v += 3;
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break;
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case 1:/* 1 Vertex of Triangle is inside of clip plane = output 1 Triangle */
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memcpy(&dst[v], &src[i], 96);
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switch(clip) {
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case FIRST_TWO_OUT:
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_glKosVertexClipZNear(&dst[v], &dst[v + 2], _glKosNearZClipMag(&CLIP_BUF[i], &CLIP_BUF[i + 2]));
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_glKosVertexClipZNear(&dst[v + 1], &dst[v + 2], _glKosNearZClipMag(&CLIP_BUF[i + 1], &CLIP_BUF[i + 2]));
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break;
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case FIRST_AND_LAST_OUT:
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_glKosVertexClipZNear(&dst[v], &dst[v + 1], _glKosNearZClipMag(&CLIP_BUF[i], &CLIP_BUF[i + 1]));
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_glKosVertexClipZNear(&dst[v + 2], &dst[v + 1], _glKosNearZClipMag(&CLIP_BUF[i + 2], &CLIP_BUF[i + 1]));
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break;
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case LAST_TWO_OUT:
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_glKosVertexClipZNear(&dst[v + 1], &dst[v], _glKosNearZClipMag(&CLIP_BUF[i + 1], &CLIP_BUF[i + 0]));
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_glKosVertexClipZNear(&dst[v + 2], &dst[v], _glKosNearZClipMag(&CLIP_BUF[i + 2], &CLIP_BUF[i + 0]));
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break;
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}
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dst[v].flags = dst[v + 1].flags = PVR_CMD_VERTEX;
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dst[v + 2].flags = PVR_CMD_VERTEX_EOL;
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v += 3;
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break;
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case 2:/* 2 Vertices of Triangle are inside of clip plane = output 2 Triangles */
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switch(clip) {
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case FIRST:
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_glKosVertexCopyPVR(&src[i + 0], &dst[v + 0]);
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_glKosVertexCopyPVR(&src[i + 1], &dst[v + 1]);
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_glKosVertexCopyPVR(&src[i + 0], &dst[v + 2]);
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_glKosVertexCopyPVR(&src[i + 2], &dst[v + 3]);
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_glKosVertexClipZNear(&dst[v + 0], &dst[v + 1], _glKosNearZClipMag(&CLIP_BUF[i], &CLIP_BUF[i + 1]));
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_glKosVertexClipZNear(&dst[v + 2], &dst[v + 3], _glKosNearZClipMag(&CLIP_BUF[i], &CLIP_BUF[i + 2]));
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break;
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case SECOND:
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_glKosVertexCopyPVR(&src[i + 1], &dst[v + 0]);
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_glKosVertexCopyPVR(&src[i + 0], &dst[v + 1]);
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_glKosVertexCopyPVR(&src[i + 1], &dst[v + 2]);
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_glKosVertexCopyPVR(&src[i + 2], &dst[v + 3]);
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_glKosVertexClipZNear(&dst[v + 0], &dst[v + 1], _glKosNearZClipMag(&CLIP_BUF[i + 1], &CLIP_BUF[i + 0]));
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_glKosVertexClipZNear(&dst[v + 2], &dst[v + 3], _glKosNearZClipMag(&CLIP_BUF[i + 1], &CLIP_BUF[i + 2]));
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break;
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case THIRD:
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_glKosVertexCopyPVR(&src[i + 2], &dst[v + 0]);
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_glKosVertexCopyPVR(&src[i + 0], &dst[v + 1]);
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_glKosVertexCopyPVR(&src[i + 2], &dst[v + 2]);
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_glKosVertexCopyPVR(&src[i + 1], &dst[v + 3]);
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_glKosVertexClipZNear(&dst[v + 0], &dst[v + 1], _glKosNearZClipMag(&CLIP_BUF[i + 2], &CLIP_BUF[i]));
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_glKosVertexClipZNear(&dst[v + 2], &dst[v + 3], _glKosNearZClipMag(&CLIP_BUF[i + 2], &CLIP_BUF[i + 1]));
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break;
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}
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dst[v + 0].flags = dst[v + 1].flags = dst[v + 2].flags = PVR_CMD_VERTEX;
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dst[v + 3].flags = PVR_CMD_VERTEX_EOL;
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v += 4;
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break;
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}
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C++;
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}
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return v;
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}
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static inline unsigned char _glKosClipTri(pvr_vertex_t *src, pvr_vertex_t *dst) {
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GLushort clip = 0; /* Clip Code for current Triangle */
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GLubyte verts_in = 0; /* # of Vertices inside clip plane for current Triangle */
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float3 clip_buf[3]; /* Store the Vertices for each Triangle Translated into Clip Space */
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/* Transform all 3 Vertices of Triangle */
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{
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register float __x __asm__("fr12") = src->x;
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register float __y __asm__("fr13") = src->y;
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register float __z __asm__("fr14") = src->z;
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mat_trans_fv12_nodiv();
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clip_buf[0].x = __x;
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clip_buf[0].y = __y;
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clip_buf[0].z = __z;
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__x = (src + 1)->x;
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__y = (src + 1)->y;
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__z = (src + 1)->z;
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mat_trans_fv12_nodiv();
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clip_buf[1].x = __x;
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clip_buf[1].y = __y;
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clip_buf[1].z = __z;
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__x = (src + 2)->x;
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__y = (src + 2)->y;
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__z = (src + 2)->z;
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mat_trans_fv12_nodiv();
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clip_buf[2].x = __x;
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clip_buf[2].y = __y;
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clip_buf[2].z = __z;
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/* Compute Clip Code for Triangle */
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(clip_buf[0].z >= CLIP_NEARZ) ? clip |= FIRST : ++verts_in;
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(clip_buf[1].z >= CLIP_NEARZ) ? clip |= SECOND : ++verts_in;
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(clip_buf[2].z >= CLIP_NEARZ) ? clip |= THIRD : ++verts_in;
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}
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switch(verts_in) { /* Start by examining # of vertices inside clip plane */
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case 0: /* All Vertices of Triangle are Outside of clip plne */
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return 0;
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case 3: /* All Vertices of Triangle are inside of clip plne */
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memcpy(dst, src, 96);
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dst->flags = (dst + 1)->flags = PVR_CMD_VERTEX;
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(dst + 2)->flags = PVR_CMD_VERTEX_EOL;
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return 3;
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case 1:/* 1 Vertex of Triangle is inside of clip plane = output 1 Triangle */
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memcpy(dst, src, 96);
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switch(clip) {
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case FIRST_TWO_OUT:
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_glKosVertexClipZNear(dst, dst + 2, _glKosNearZClipMag(&clip_buf[0], &clip_buf[2]));
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_glKosVertexClipZNear(dst + 1, dst + 2, _glKosNearZClipMag(&clip_buf[1], &clip_buf[2]));
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break;
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case FIRST_AND_LAST_OUT:
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_glKosVertexClipZNear(dst, dst + 1, _glKosNearZClipMag(&clip_buf[0], &clip_buf[1]));
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_glKosVertexClipZNear(dst + 2, dst + 1, _glKosNearZClipMag(&clip_buf[2], &clip_buf[1]));
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break;
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case LAST_TWO_OUT:
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_glKosVertexClipZNear(dst + 1, dst, _glKosNearZClipMag(&clip_buf[1], &clip_buf[0]));
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_glKosVertexClipZNear(dst + 2, dst, _glKosNearZClipMag(&clip_buf[2], &clip_buf[0]));
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break;
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}
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dst->flags = (dst + 1)->flags = PVR_CMD_VERTEX;
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(dst + 2)->flags = PVR_CMD_VERTEX_EOL;
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return 3;
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case 2:/* 2 Vertices of Triangle are inside of clip plane = output 2 Triangles */
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switch(clip) {
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case FIRST:
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memcpy(dst, src, 64);
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_glKosVertexCopyPVR(src, dst + 2);
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_glKosVertexCopyPVR(src + 2, dst + 3);
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_glKosVertexClipZNear(dst, dst + 1, _glKosNearZClipMag(&clip_buf[0], &clip_buf[1]));
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_glKosVertexClipZNear(dst + 2, dst + 3, _glKosNearZClipMag(&clip_buf[0], &clip_buf[2]));
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break;
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case SECOND:
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_glKosVertexCopyPVR(src + 1, dst);
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_glKosVertexCopyPVR(src, dst + 1);
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memcpy(dst + 2, src + 1, 64);
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_glKosVertexClipZNear(dst, dst + 1, _glKosNearZClipMag(&clip_buf[1], &clip_buf[0]));
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_glKosVertexClipZNear(dst + 2, dst + 3, _glKosNearZClipMag(&clip_buf[1], &clip_buf[2]));
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break;
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case THIRD:
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_glKosVertexCopyPVR(src + 2, dst);
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_glKosVertexCopyPVR(src, dst + 1);
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_glKosVertexCopyPVR(src + 2, dst + 2);
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_glKosVertexCopyPVR(src + 1, dst + 3);
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_glKosVertexClipZNear(dst, dst + 1, _glKosNearZClipMag(&clip_buf[2], &clip_buf[0]));
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_glKosVertexClipZNear(dst + 2, dst + 3, _glKosNearZClipMag(&clip_buf[2], &clip_buf[1]));
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break;
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}
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dst->flags = (dst + 1)->flags = (dst + 2)->flags = PVR_CMD_VERTEX;
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(dst + 3)->flags = PVR_CMD_VERTEX_EOL;
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return 4;
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}
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return 0;
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}
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GLuint _glKosClipTriangles(pvr_vertex_t *src, pvr_vertex_t *dst, GLuint vertices) {
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GLuint i, v = 0;
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for(i = 0; i < vertices; i += 3) /* Iterate all Triangles */
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v += _glKosClipTri(src + i, dst + v);
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return v;
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}
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GLuint _glKosClipQuads(pvr_vertex_t *src, pvr_vertex_t *dst, GLuint vertices) {
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GLuint i, v = 0;
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pvr_vertex_t qv;
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for(i = 0; i < vertices; i += 4) { /* Iterate all Quads, Rearranging into Triangle Strips */
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_glKosVertexCopyPVR(src + i + 3, &qv);
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_glKosVertexCopyPVR(src + i + 2, src + i + 3);
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_glKosVertexCopyPVR(&qv, src + i + 2);
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v += _glKosClipTriangleStrip(src + i, dst + v, 4);
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}
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return v;
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}
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