337 lines
12 KiB
C
337 lines
12 KiB
C
#include <float.h>
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#include <stdio.h>
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#ifdef _arch_dreamcast
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#include <dc/pvr.h>
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#else
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#define PVR_PACK_COLOR(a, r, g, b) {}
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#endif
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#include "clip.h"
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#include "../containers/aligned_vector.h"
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static unsigned char ZCLIP_ENABLED = 1;
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unsigned char isClippingEnabled() {
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return ZCLIP_ENABLED;
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}
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void enableClipping(unsigned char v) {
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ZCLIP_ENABLED = v;
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}
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void clipLineToNearZ(const ClipVertex* v1, const ClipVertex* v2, ClipVertex* vout, float* t) {
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const float NEAR_PLANE = 0.2; // FIXME: this needs to be read from the projection matrix.. somehow
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*t = (NEAR_PLANE - v1->w) / (v2->w - v1->w);
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float vec [] = {v2->xyz[0] - v1->xyz[0], v2->xyz[1] - v1->xyz[1], v2->xyz[2] - v1->xyz[2]};
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vout->xyz[0] = v1->xyz[0] + (vec[0] * (*t));
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vout->xyz[1] = v1->xyz[1] + (vec[1] * (*t));
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vout->xyz[2] = v1->xyz[2] + (vec[2] * (*t));
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}
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static inline void interpolateFloat(const float v1, const float v2, const float t, float* out) {
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float v = v2 - v1;
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*out = (v * t) + v1;
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}
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static void interpolateVec2(const float* v1, const float* v2, const float t, float* out) {
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/* FIXME: SH4 has an asm instruction for this */
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interpolateFloat(v1[0], v2[0], t, &out[0]);
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interpolateFloat(v1[1], v2[1], t, &out[1]);
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}
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static void interpolateVec3(const float* v1, const float* v2, const float t, float* out) {
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/* FIXME: SH4 has an asm instruction for this */
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interpolateFloat(v1[0], v2[0], t, &out[0]);
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interpolateFloat(v1[1], v2[1], t, &out[1]);
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interpolateFloat(v1[2], v2[2], t, &out[2]);
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}
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static void interpolateVec4(const float* v1, const float* v2, const float t, float* out) {
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/* FIXME: SH4 has an asm instruction for this */
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interpolateFloat(v1[0], v2[0], t, &out[0]);
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interpolateFloat(v1[1], v2[1], t, &out[1]);
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interpolateFloat(v1[2], v2[2], t, &out[2]);
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interpolateFloat(v1[3], v2[3], t, &out[3]);
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}
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const uint32_t VERTEX_CMD_EOL = 0xf0000000;
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const uint32_t VERTEX_CMD = 0xe0000000;
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void clipTriangleStrip(AlignedVector* vertices, AlignedVector* outBuffer) __attribute__((optimize("fast-math")));
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void clipTriangleStrip(AlignedVector* vertices, AlignedVector* outBuffer) {
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/* Clipping triangle strips is *hard* this is the algorithm we follow:
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*
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* - Treat each triangle in the strip individually.
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* - If we find a triangle that needs clipping, treat it in isolation.
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* - End the strip at the triangle
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* - Generate a new single-triangle strip for it
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* - Begin a new strip for the remainder of the strip
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*
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* There is probably more efficient way but there are so many different cases to handle that it's
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* difficult to even write them down!
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*/
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uint32_t i;
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uint32_t stripCount = 2; /* The number of vertices in the source strip so far */
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for(i = 2; i < vertices->size; ++i) {
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if(stripCount < 2) {
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stripCount++;
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continue;
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}
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ClipVertex* thisVertex = aligned_vector_at(vertices, i);
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ClipVertex* sourceTriangle[3] = {
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aligned_vector_at(vertices, i - 2),
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aligned_vector_at(vertices, i - 1),
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thisVertex
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};
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/* If we're on an odd vertex, we need to swap the order of the first two vertices, as that's what
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* triangle strips do */
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uint8_t swap = stripCount > 2 && (stripCount % 2 != 0);
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ClipVertex* v1 = swap ? sourceTriangle[1] : sourceTriangle[0];
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ClipVertex* v2 = swap ? sourceTriangle[0] : sourceTriangle[1];
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ClipVertex* v3 = sourceTriangle[2];
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uint8_t visible = ((v1->w > 0) ? 4 : 0) | ((v2->w > 0) ? 2 : 0) | ((v3->w > 0) ? 1 : 0);
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uint8_t startOfStrip = (i == 2) || (outBuffer->size > 2 && ((ClipVertex*) aligned_vector_back(outBuffer))->flags == VERTEX_CMD_EOL);
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/* All visible, we're fine! */
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if(visible == 0b111) {
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if(startOfStrip) {
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aligned_vector_push_back(outBuffer, v1, 1);
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aligned_vector_push_back(outBuffer, v2, 1);
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}
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aligned_vector_push_back(outBuffer, v3, 1);
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} else if(visible == 0b000) {
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/* Do nothing */
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continue;
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} else if(visible == 0b100) {
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/* Only the first vertex is visible */
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float t1 = 0, t2 = 0;
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ClipVertex output[3];
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clipLineToNearZ(v1, v2, &output[1], &t1);
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clipLineToNearZ(v1, v3, &output[2], &t2);
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interpolateFloat(v1->w, v2->w, t1, &output[1].w);
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interpolateFloat(v1->w, v3->w, t2, &output[2].w);
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output[0] = *v1;
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/* Interpolate normals */
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interpolateVec3(v1->nxyz, v2->nxyz, t1, output[1].nxyz);
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interpolateVec3(v1->nxyz, v3->nxyz, t2, output[2].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v1->uv, v2->uv, t1, output[1].uv);
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interpolateVec2(v1->uv, v3->uv, t2, output[2].uv);
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interpolateVec2(v1->st, v2->st, t1, output[1].st);
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interpolateVec2(v1->st, v3->st, t2, output[2].st);
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interpolateVec4(v1->diffuse, v2->diffuse, t1, output[1].diffuse);
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interpolateVec4(v1->diffuse, v3->diffuse, t2, output[2].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 3);
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} else if(visible == 0b010) {
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/* Only the second vertex is visible */
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float t1 = 0, t2 = 0;
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ClipVertex output[3];
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clipLineToNearZ(v2, v1, &output[0], &t1);
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clipLineToNearZ(v2, v3, &output[2], &t2);
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interpolateFloat(v2->w, v1->w, t1, &output[0].w);
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interpolateFloat(v2->w, v3->w, t2, &output[2].w);
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output[1] = *v2;
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/* Interpolate normals */
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interpolateVec3(v2->nxyz, v1->nxyz, t1, output[0].nxyz);
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interpolateVec3(v2->nxyz, v3->nxyz, t2, output[2].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v2->uv, v1->uv, t1, output[0].uv);
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interpolateVec2(v2->uv, v3->uv, t2, output[2].uv);
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interpolateVec2(v2->st, v1->st, t1, output[0].st);
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interpolateVec2(v2->st, v3->st, t2, output[2].st);
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interpolateVec4(v2->diffuse, v1->diffuse, t1, output[0].diffuse);
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interpolateVec4(v2->diffuse, v3->diffuse, t2, output[2].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 3);
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} else if(visible == 0b001) {
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/* Only the third vertex is visible */
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float t1 = 0, t2 = 0;
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ClipVertex output[3];
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clipLineToNearZ(v3, v1, &output[0], &t1);
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clipLineToNearZ(v3, v2, &output[1], &t2);
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interpolateFloat(v3->w, v1->w, t1, &output[0].w);
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interpolateFloat(v3->w, v2->w, t2, &output[1].w);
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output[2] = *v3;
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/* Interpolate normals */
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interpolateVec3(v3->nxyz, v1->nxyz, t1, output[0].nxyz);
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interpolateVec3(v3->nxyz, v2->nxyz, t2, output[1].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v3->uv, v1->uv, t1, output[0].uv);
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interpolateVec2(v3->uv, v2->uv, t2, output[1].uv);
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interpolateVec2(v3->st, v1->st, t1, output[0].st);
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interpolateVec2(v3->st, v2->st, t2, output[1].st);
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interpolateVec4(v3->diffuse, v1->diffuse, t1, output[0].diffuse);
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interpolateVec4(v3->diffuse, v2->diffuse, t2, output[1].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 3);
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} else if(visible == 0b110) {
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/* Third vertex isn't visible */
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float t1 = 0, t2 = 0;
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ClipVertex output[4];
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clipLineToNearZ(v2, v3, &output[2], &t1);
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clipLineToNearZ(v1, v3, &output[3], &t2);
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interpolateFloat(v2->w, v3->w, t1, &output[2].w);
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interpolateFloat(v1->w, v3->w, t2, &output[3].w);
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output[0] = *v1;
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output[1] = *v2;
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/* Interpolate normals */
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interpolateVec3(v2->nxyz, v3->nxyz, t1, output[2].nxyz);
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interpolateVec3(v1->nxyz, v3->nxyz, t2, output[3].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v2->uv, v3->uv, t1, output[2].uv);
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interpolateVec2(v1->uv, v3->uv, t2, output[3].uv);
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interpolateVec2(v2->st, v3->st, t1, output[2].st);
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interpolateVec2(v1->st, v3->st, t2, output[3].st);
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interpolateVec4(v2->diffuse, v3->diffuse, t1, output[2].diffuse);
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interpolateVec4(v1->diffuse, v3->diffuse, t2, output[3].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD;
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output[3].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 4);
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} else if(visible == 0b011) {
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/* First vertex isn't visible, so let's clip along the lines to the second and third */
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float t1 = 0, t2 = 0;
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ClipVertex output[4];
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clipLineToNearZ(v1, v2, &output[0], &t1);
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clipLineToNearZ(v1, v3, &output[2], &t2);
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interpolateFloat(v1->w, v2->w, t1, &output[0].w);
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interpolateFloat(v1->w, v3->w, t2, &output[2].w);
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output[1] = *v2;
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output[3] = *v3;
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/* Interpolate normals */
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interpolateVec3(v1->nxyz, v2->nxyz, t1, output[0].nxyz);
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interpolateVec3(v1->nxyz, v3->nxyz, t2, output[2].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v1->uv, v2->uv, t1, output[0].uv);
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interpolateVec2(v1->uv, v3->uv, t2, output[2].uv);
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interpolateVec2(v1->st, v2->st, t1, output[0].st);
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interpolateVec2(v1->st, v3->st, t2, output[2].st);
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interpolateVec4(v1->diffuse, v2->diffuse, t1, output[0].diffuse);
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interpolateVec4(v1->diffuse, v3->diffuse, t2, output[2].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD;
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output[3].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 4);
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} else if(visible == 0b101) {
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/* Second vertex isn't visible */
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float t1 = 0, t2 = 0;
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ClipVertex output[4];
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clipLineToNearZ(v1, v2, &output[1], &t1);
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clipLineToNearZ(v3, v2, &output[3], &t2);
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interpolateFloat(v1->w, v2->w, t1, &output[1].w);
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interpolateFloat(v3->w, v2->w, t2, &output[3].w);
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output[0] = *v1;
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output[2] = *v3;
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/* Interpolate normals */
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interpolateVec3(v1->nxyz, v2->nxyz, t1, output[1].nxyz);
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interpolateVec3(v3->nxyz, v2->nxyz, t2, output[3].nxyz);
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/* Interpolate texcoords */
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interpolateVec2(v1->uv, v2->uv, t1, output[1].uv);
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interpolateVec2(v3->uv, v2->uv, t2, output[3].uv);
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interpolateVec2(v1->st, v2->st, t1, output[1].st);
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interpolateVec2(v3->st, v2->st, t2, output[3].st);
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interpolateVec4(v1->diffuse, v2->diffuse, t1, output[1].diffuse);
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interpolateVec4(v3->diffuse, v2->diffuse, t2, output[3].diffuse);
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output[0].flags = VERTEX_CMD;
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output[1].flags = VERTEX_CMD;
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output[2].flags = VERTEX_CMD;
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output[3].flags = VERTEX_CMD_EOL;
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aligned_vector_push_back(outBuffer, output, 4);
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}
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/* If this vertex was the last in the list, reset the stripCount */
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if(thisVertex->flags == VERTEX_CMD_EOL) {
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stripCount = 0;
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} else {
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stripCount++;
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}
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}
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}
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