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Fix clipping 2020

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This commit is contained in:
Luke Benstead 2020-04-03 19:12:42 +00:00
parent 4292304df1
commit cf90d10cb9
4 changed files with 97 additions and 96 deletions
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174
GL/clip.c
View File

@ -2,6 +2,8 @@
#include <stdio.h>
#include <assert.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#ifdef _arch_dreamcast
#include <dc/pvr.h>
@ -23,21 +25,30 @@ void _glEnableClipping(unsigned char v) {
ZCLIP_ENABLED = v;
}
void inline _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout, float* t) {
inline float _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout) {
const float d0 = v1->w + v1->xyz[2];
const float d1 = v2->w + v2->xyz[2];
*t = d0 / (d0 - d1);
/* We need to shift 't' a little, to avoid the possibility that a
* rounding error leaves the new vertex behind the near plane. We shift
* according to the direction we're clipping across the plane */
const float epsilon = (d0 < d1) ? -0.000001 : 0.000001;
const float vec [] = {
v2->xyz[0] - v1->xyz[0],
v2->xyz[1] - v1->xyz[1],
v2->xyz[2] - v1->xyz[2]
};
float t = MATH_Fast_Divide(d0, (d0 - d1)) + epsilon;
vout->xyz[0] = MATH_fmac(vec[0], (*t), v1->xyz[0]);
vout->xyz[1] = MATH_fmac(vec[1], (*t), v1->xyz[1]);
vout->xyz[2] = MATH_fmac(vec[2], (*t), v1->xyz[2]);
vout->xyz[0] = MATH_fmac(v2->xyz[0] - v1->xyz[0], t, v1->xyz[0]);
vout->xyz[1] = MATH_fmac(v2->xyz[1] - v1->xyz[1], t, v1->xyz[1]);
vout->xyz[2] = MATH_fmac(v2->xyz[2] - v1->xyz[2], t, v1->xyz[2]);
/*
printf(
"(%f, %f, %f, %f) -> %f -> (%f, %f, %f, %f) = (%f, %f, %f)\n",
v1->xyz[0], v1->xyz[1], v1->xyz[2], v1->w, t,
v2->xyz[0], v2->xyz[1], v2->xyz[2], v2->w,
vout->xyz[0], vout->xyz[1], vout->xyz[2]
);*/
return t;
}
GL_FORCE_INLINE void interpolateFloat(const float v1, const float v2, const float t, float* out) {
@ -78,11 +89,7 @@ typedef struct {
uint8_t visible;
} Triangle;
void _glClipTriangle(const Triangle* triangle, const uint8_t visible, SubmissionTarget* target, const uint8_t flatShade) __attribute__((optimize("fast-math")));
void _glClipTriangle(const Triangle* triangle, const uint8_t visible, SubmissionTarget* target, const uint8_t flatShade) {
uint8_t i, c = 0;
uint8_t lastVisible = 255;
Vertex* last = NULL;
VertexExtra* veLast = NULL;
@ -94,90 +101,79 @@ void _glClipTriangle(const Triangle* triangle, const uint8_t visible, Submission
/* Used when flat shading is enabled */
uint32_t finalColour = *((uint32_t*) bgra);
for(i = 0; i < 4; ++i) {
uint8_t thisIndex = (i == 3) ? 0 : i;
Vertex tmp;
VertexExtra veTmp;
Vertex next;
VertexExtra veNext;
uint8_t pushedCount = 0;
next.flags = VERTEX_CMD;
#define IS_VISIBLE(x) (visible & (1 << (2 - (x)))) > 0
uint8_t thisVisible = (visible & (1 << (2 - thisIndex))) > 0;
if(i > 0) {
uint8_t lastIndex = (i == 3) ? 2 : thisIndex - 1;
#define PUSH_VERT(vert, ve) \
last = aligned_vector_push_back(&target->output->vector, vert, 1); \
last->flags = VERTEX_CMD; \
veLast = aligned_vector_push_back(target->extras, ve, 1); \
++pushedCount;
if(lastVisible < 255 && lastVisible != thisVisible) {
const Vertex* v1 = &vertices[lastIndex];
const Vertex* v2 = &vertices[thisIndex];
#define CLIP_TO_PLANE(vert1, ve1, vert2, ve2) \
do { \
float t = _glClipLineToNearZ((vert1), (vert2), &tmp); \
interpolateFloat((vert1)->w, (vert2)->w, t, &tmp.w); \
interpolateVec2((vert1)->uv, (vert2)->uv, t, tmp.uv); \
interpolateVec3((ve1)->nxyz, (ve2)->nxyz, t, veTmp.nxyz); \
interpolateVec2((ve1)->st, (ve2)->st, t, veTmp.st); \
if(flatShade) { \
interpolateColour((const uint8_t*) &finalColour, (const uint8_t*) &finalColour, t, tmp.bgra); \
} else { interpolateColour((vert1)->bgra, (vert2)->bgra, t, tmp.bgra); } \
} while(0); \
const VertexExtra* ve1 = &extras[lastIndex];
const VertexExtra* ve2 = &extras[thisIndex];
float t;
_glClipLineToNearZ(v1, v2, &next, &t);
interpolateFloat(v1->w, v2->w, t, &next.w);
interpolateVec2(v1->uv, v2->uv, t, next.uv);
interpolateVec3(ve1->nxyz, ve2->nxyz, t, veNext.nxyz);
interpolateVec2(ve1->st, ve2->st, t, veNext.st);
if(flatShade) {
char* next_bgra = (char*) next.bgra;
*((uint32_t*) next_bgra) = finalColour;
} else {
interpolateColour(v1->bgra, v2->bgra, t, next.bgra);
}
/* Push back the new vertices to the end of both the ClipVertex and VertexExtra lists */
last = aligned_vector_push_back(&target->output->vector, &next, 1);
last->flags = VERTEX_CMD;
veLast = aligned_vector_push_back(target->extras, &veNext, 1);
++c;
}
}
if(thisVisible && i != 3) {
last = aligned_vector_push_back(&target->output->vector, &vertices[thisIndex], 1);
last->flags = VERTEX_CMD;
veLast = aligned_vector_push_back(target->extras, &extras[thisIndex], 1);
++c;
}
lastVisible = thisVisible;
uint8_t v0 = IS_VISIBLE(0);
uint8_t v1 = IS_VISIBLE(1);
uint8_t v2 = IS_VISIBLE(2);
if(v0) {
PUSH_VERT(&vertices[0], &extras[0]);
}
if(last) {
if(c == 4) {
/* Convert to two triangles */
Vertex newVerts[3];
newVerts[0] = *(last - 3);
newVerts[1] = *(last - 1);
newVerts[2] = *(last);
if(v0 != v1) {
CLIP_TO_PLANE(&vertices[0], &extras[0], &vertices[1], &extras[1]);
PUSH_VERT(&tmp, &veTmp);
}
VertexExtra newExtras[3];
newExtras[0] = *(veLast - 3);
newExtras[1] = *(veLast - 1);
newExtras[2] = *(veLast);
if(v1) {
PUSH_VERT(&vertices[1], &extras[1]);
}
(last - 1)->flags = VERTEX_CMD_EOL;
newVerts[0].flags = VERTEX_CMD;
newVerts[1].flags = VERTEX_CMD;
newVerts[2].flags = VERTEX_CMD_EOL;
if(v1 != v2) {
CLIP_TO_PLANE(&vertices[1], &extras[1], &vertices[2], &extras[2]);
PUSH_VERT(&tmp, &veTmp);
}
aligned_vector_resize(&target->output->vector, target->output->vector.size - 1);
aligned_vector_push_back(&target->output->vector, newVerts, 3);
if(v2) {
PUSH_VERT(&vertices[2], &extras[2]);
}
aligned_vector_resize(target->extras, target->extras->size - 1);
aligned_vector_push_back(target->extras, newExtras, 3);
} else {
last->flags = VERTEX_CMD_EOL;
}
if(v2 != v0) {
CLIP_TO_PLANE(&vertices[2], &extras[2], &vertices[0], &extras[0]);
PUSH_VERT(&tmp, &veTmp);
}
if(pushedCount == 4) {
Vertex* prev = last - 1;
VertexExtra* prevVe = veLast - 1;
tmp = *prev;
veTmp = *prevVe;
*prev = *last;
*prevVe = *veLast;
*last = tmp;
*veLast = veTmp;
prev->flags = VERTEX_CMD;
last->flags = VERTEX_CMD_EOL;
} else {
/* Set the last flag to the end of the new strip */
last->flags = VERTEX_CMD_EOL;
}
}
@ -255,9 +251,9 @@ void _glClipTriangleStrip(SubmissionTarget* target, uint8_t fladeShade) {
* and it's in front of the near plane (Z > -W)
*/
uint8_t visible = (
((v1->w > 0 && v1->xyz[2] >= -v1->w) ? 4 : 0) |
((v2->w > 0 && v2->xyz[2] >= -v2->w) ? 2 : 0) |
((v3->w > 0 && v3->xyz[2] >= -v3->w) ? 1 : 0)
((v1->w >= 0 && v1->xyz[2] >= -v1->w) ? 4 : 0) |
((v2->w >= 0 && v2->xyz[2] >= -v2->w) ? 2 : 0) |
((v3->w >= 0 && v3->xyz[2] >= -v3->w) ? 1 : 0)
);
switch(visible) {

12
GL/draw.c
View File

@ -1321,10 +1321,10 @@ GL_FORCE_INLINE void submitVertices(GLenum mode, GLsizei first, GLuint count, GL
uint32_t i = 0;
fprintf(stderr, "=========\n");
for(i = offset; i < activeList->vector.size; ++i) {
ClipVertex* v = aligned_vector_at(&activeList->vector, i);
for(i = 0; i < target->count; ++i) {
Vertex* v = aligned_vector_at(&target->output->vector, target->start_offset + i);
if(v->flags == 0xe0000000 || v->flags == 0xf0000000) {
fprintf(stderr, "(%f, %f, %f) -> %x\n", v->xyz[0], v->xyz[1], v->xyz[2], v->flags);
fprintf(stderr, "(%f, %f, %f, %f) -> %x\n", v->xyz[0], v->xyz[1], v->xyz[2], v->w, v->flags);
} else {
fprintf(stderr, "%x\n", *((uint32_t*)v));
}
@ -1337,10 +1337,10 @@ GL_FORCE_INLINE void submitVertices(GLenum mode, GLsizei first, GLuint count, GL
#if DEBUG_CLIPPING
fprintf(stderr, "--------\n");
for(i = offset; i < activeList->vector.size; ++i) {
ClipVertex* v = aligned_vector_at(&activeList->vector, i);
for(i = 0; i < target->count; ++i) {
Vertex* v = aligned_vector_at(&target->output->vector, target->start_offset + i);
if(v->flags == 0xe0000000 || v->flags == 0xf0000000) {
fprintf(stderr, "(%f, %f, %f) -> %x\n", v->xyz[0], v->xyz[1], v->xyz[2], v->flags);
fprintf(stderr, "(%f, %f, %f, %f) -> %x\n", v->xyz[0], v->xyz[1], v->xyz[2], v->w, v->flags);
} else {
fprintf(stderr, "%x\n", *((uint32_t*)v));
}

2
GL/private.h
View File

@ -239,7 +239,7 @@ typedef enum {
struct SubmissionTarget;
void _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout, float* t);
float _glClipLineToNearZ(const Vertex* v1, const Vertex* v2, Vertex* vout);
void _glClipTriangleStrip(SubmissionTarget* target, uint8_t fladeShade);
PolyList *_glActivePolyList();

5
samples/zclip_triangle/main.c
View File

@ -44,6 +44,7 @@ void ReSizeGLScene(int Width, int Height)
/* The main drawing function. */
void DrawGLScene()
{
static GLfloat rotation = 0.0f;
static GLfloat movement = 0.0f;
static GLboolean increasing = GL_TRUE;
@ -59,6 +60,9 @@ void DrawGLScene()
movement -= 0.05f;
}
rotation += 0.5f;
rotation = (rotation > 360.0f) ? rotation - 360.0f : rotation;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Clear The Screen And The Depth Buffer
glLoadIdentity(); // Reset The View
@ -66,6 +70,7 @@ void DrawGLScene()
glPushMatrix();
glTranslatef(0.0f, -1.0f, movement);
glRotatef(rotation, 0.0f, 1.0f, 0.0f);
glBegin(GL_TRIANGLES);
glColor3f(1.0f, 0.0f, 0.0f);