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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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162
GL/clip.c
View File

@ -2,6 +2,8 @@
#include <stdio.h> #include <stdio.h>
#include <assert.h> #include <assert.h>
#include <string.h> #include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#ifdef _arch_dreamcast #ifdef _arch_dreamcast
#include <dc/pvr.h> #include <dc/pvr.h>
@ -23,21 +25,30 @@ void _glEnableClipping(unsigned char v) {
ZCLIP_ENABLED = 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 d0 = v1->w + v1->xyz[2];
const float d1 = v2->w + v2->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 [] = { float t = MATH_Fast_Divide(d0, (d0 - d1)) + epsilon;
v2->xyz[0] - v1->xyz[0],
v2->xyz[1] - v1->xyz[1],
v2->xyz[2] - v1->xyz[2]
};
vout->xyz[0] = MATH_fmac(vec[0], (*t), v1->xyz[0]); vout->xyz[0] = MATH_fmac(v2->xyz[0] - v1->xyz[0], t, v1->xyz[0]);
vout->xyz[1] = MATH_fmac(vec[1], (*t), v1->xyz[1]); vout->xyz[1] = MATH_fmac(v2->xyz[1] - v1->xyz[1], t, v1->xyz[1]);
vout->xyz[2] = MATH_fmac(vec[2], (*t), v1->xyz[2]); 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) { 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; uint8_t visible;
} Triangle; } 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) { 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; Vertex* last = NULL;
VertexExtra* veLast = NULL; VertexExtra* veLast = NULL;
@ -94,90 +101,79 @@ void _glClipTriangle(const Triangle* triangle, const uint8_t visible, Submission
/* Used when flat shading is enabled */ /* Used when flat shading is enabled */
uint32_t finalColour = *((uint32_t*) bgra); uint32_t finalColour = *((uint32_t*) bgra);
for(i = 0; i < 4; ++i) { Vertex tmp;
uint8_t thisIndex = (i == 3) ? 0 : i; VertexExtra veTmp;
Vertex next; uint8_t pushedCount = 0;
VertexExtra veNext;
next.flags = VERTEX_CMD; #define IS_VISIBLE(x) (visible & (1 << (2 - (x)))) > 0
uint8_t thisVisible = (visible & (1 << (2 - thisIndex))) > 0; #define PUSH_VERT(vert, ve) \
if(i > 0) { last = aligned_vector_push_back(&target->output->vector, vert, 1); \
uint8_t lastIndex = (i == 3) ? 2 : thisIndex - 1; last->flags = VERTEX_CMD; \
veLast = aligned_vector_push_back(target->extras, ve, 1); \
++pushedCount;
if(lastVisible < 255 && lastVisible != thisVisible) { #define CLIP_TO_PLANE(vert1, ve1, vert2, ve2) \
const Vertex* v1 = &vertices[lastIndex]; do { \
const Vertex* v2 = &vertices[thisIndex]; 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]; uint8_t v0 = IS_VISIBLE(0);
const VertexExtra* ve2 = &extras[thisIndex]; uint8_t v1 = IS_VISIBLE(1);
uint8_t v2 = IS_VISIBLE(2);
float t; if(v0) {
PUSH_VERT(&vertices[0], &extras[0]);
_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 */ if(v0 != v1) {
last = aligned_vector_push_back(&target->output->vector, &next, 1); CLIP_TO_PLANE(&vertices[0], &extras[0], &vertices[1], &extras[1]);
last->flags = VERTEX_CMD; PUSH_VERT(&tmp, &veTmp);
veLast = aligned_vector_push_back(target->extras, &veNext, 1);
++c;
}
} }
if(thisVisible && i != 3) { if(v1) {
last = aligned_vector_push_back(&target->output->vector, &vertices[thisIndex], 1); PUSH_VERT(&vertices[1], &extras[1]);
last->flags = VERTEX_CMD;
veLast = aligned_vector_push_back(target->extras, &extras[thisIndex], 1);
++c;
} }
lastVisible = thisVisible; if(v1 != v2) {
CLIP_TO_PLANE(&vertices[1], &extras[1], &vertices[2], &extras[2]);
PUSH_VERT(&tmp, &veTmp);
} }
if(last) { if(v2) {
if(c == 4) { PUSH_VERT(&vertices[2], &extras[2]);
/* Convert to two triangles */ }
Vertex newVerts[3];
newVerts[0] = *(last - 3);
newVerts[1] = *(last - 1);
newVerts[2] = *(last);
VertexExtra newExtras[3]; if(v2 != v0) {
newExtras[0] = *(veLast - 3); CLIP_TO_PLANE(&vertices[2], &extras[2], &vertices[0], &extras[0]);
newExtras[1] = *(veLast - 1); PUSH_VERT(&tmp, &veTmp);
newExtras[2] = *(veLast); }
(last - 1)->flags = VERTEX_CMD_EOL; if(pushedCount == 4) {
newVerts[0].flags = VERTEX_CMD; Vertex* prev = last - 1;
newVerts[1].flags = VERTEX_CMD; VertexExtra* prevVe = veLast - 1;
newVerts[2].flags = VERTEX_CMD_EOL;
aligned_vector_resize(&target->output->vector, target->output->vector.size - 1); tmp = *prev;
aligned_vector_push_back(&target->output->vector, newVerts, 3); veTmp = *prevVe;
aligned_vector_resize(target->extras, target->extras->size - 1); *prev = *last;
aligned_vector_push_back(target->extras, newExtras, 3); *prevVe = *veLast;
} else {
*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; 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) * and it's in front of the near plane (Z > -W)
*/ */
uint8_t visible = ( uint8_t visible = (
((v1->w > 0 && v1->xyz[2] >= -v1->w) ? 4 : 0) | ((v1->w >= 0 && v1->xyz[2] >= -v1->w) ? 4 : 0) |
((v2->w > 0 && v2->xyz[2] >= -v2->w) ? 2 : 0) | ((v2->w >= 0 && v2->xyz[2] >= -v2->w) ? 2 : 0) |
((v3->w > 0 && v3->xyz[2] >= -v3->w) ? 1 : 0) ((v3->w >= 0 && v3->xyz[2] >= -v3->w) ? 1 : 0)
); );
switch(visible) { 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; uint32_t i = 0;
fprintf(stderr, "=========\n"); fprintf(stderr, "=========\n");
for(i = offset; i < activeList->vector.size; ++i) { for(i = 0; i < target->count; ++i) {
ClipVertex* v = aligned_vector_at(&activeList->vector, i); Vertex* v = aligned_vector_at(&target->output->vector, target->start_offset + i);
if(v->flags == 0xe0000000 || v->flags == 0xf0000000) { 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 { } else {
fprintf(stderr, "%x\n", *((uint32_t*)v)); 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 #if DEBUG_CLIPPING
fprintf(stderr, "--------\n"); fprintf(stderr, "--------\n");
for(i = offset; i < activeList->vector.size; ++i) { for(i = 0; i < target->count; ++i) {
ClipVertex* v = aligned_vector_at(&activeList->vector, i); Vertex* v = aligned_vector_at(&target->output->vector, target->start_offset + i);
if(v->flags == 0xe0000000 || v->flags == 0xf0000000) { 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 { } else {
fprintf(stderr, "%x\n", *((uint32_t*)v)); fprintf(stderr, "%x\n", *((uint32_t*)v));
} }

2
GL/private.h
View File

@ -239,7 +239,7 @@ typedef enum {
struct SubmissionTarget; 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); void _glClipTriangleStrip(SubmissionTarget* target, uint8_t fladeShade);
PolyList *_glActivePolyList(); PolyList *_glActivePolyList();

5
samples/zclip_triangle/main.c
View File

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