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/* $Id: depth.c,v 1.5 1996/10/09 03:07:25 brianp Exp $ */
/*
* Mesa 3-D graphics library
* Version: 2.0
* Copyright (C) 1995-1996 Brian Paul
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* $Log: depth.c,v $
* Revision 1.5 1996/10/09 03:07:25 brianp
* replaced malloc with calloc in gl_alloc_depth_buffer()
*
* Revision 1.4 1996/09/27 01:24:58 brianp
* added missing default cases to switches
*
* Revision 1.3 1996/09/19 00:54:05 brianp
* added missing returns after some gl_error() calls
*
* Revision 1.2 1996/09/15 14:19:16 brianp
* now use GLframebuffer and GLvisual
*
* Revision 1.1 1996/09/13 01:38:16 brianp
* Initial revision
*
*/
/*
* Depth buffer functions
*/
#include <stdlib.h>
#include <string.h>
#include "context.h"
#include "depth.h"
#include "dlist.h"
#include "macros.h"
#include "types.h"
/**********************************************************************/
/***** API Functions *****/
/**********************************************************************/
void gl_ClearDepth( GLcontext* ctx, GLclampd depth )
{
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glClearDepth" );
return;
}
ctx->Depth.Clear = (GLfloat) CLAMP( depth, 0.0, 1.0 );
}
void gl_DepthFunc( GLcontext* ctx, GLenum func )
{
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glDepthFunc" );
return;
}
switch (func) {
case GL_NEVER:
case GL_LESS: /* (default) pass if incoming z < stored z */
case GL_GEQUAL:
case GL_LEQUAL:
case GL_GREATER:
case GL_NOTEQUAL:
case GL_EQUAL:
case GL_ALWAYS:
ctx->Depth.Func = func;
ctx->NewState |= NEW_RASTER_OPS;
break;
default:
gl_error( ctx, GL_INVALID_ENUM, "glDepth.Func" );
}
}
void gl_DepthMask( GLcontext* ctx, GLboolean flag )
{
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glDepthMask" );
return;
}
/*
* GL_TRUE indicates depth buffer writing is enabled (default)
* GL_FALSE indicates depth buffer writing is disabled
*/
ctx->Depth.Mask = flag;
ctx->NewState |= NEW_RASTER_OPS;
}
void gl_DepthRange( GLcontext* ctx, GLclampd nearval, GLclampd farval )
{
/*
* nearval - specifies mapping of the near clipping plane to window
* coordinates, default is 0
* farval - specifies mapping of the far clipping plane to window
* coordinates, default is 1
*
* After clipping and div by w, z coords are in -1.0 to 1.0,
* corresponding to near and far clipping planes. glDepthRange
* specifies a linear mapping of the normalized z coords in
* this range to window z coords.
*/
GLfloat n, f;
if (INSIDE_BEGIN_END(ctx)) {
gl_error( ctx, GL_INVALID_OPERATION, "glDepthRange" );
return;
}
n = (GLfloat) CLAMP( nearval, 0.0, 1.0 );
f = (GLfloat) CLAMP( farval, 0.0, 1.0 );
ctx->Viewport.Near = n;
ctx->Viewport.Far = f;
ctx->Viewport.Sz = (f - n) / 2.0;
ctx->Viewport.Tz = (f - n) / 2.0 + n;
}
/**********************************************************************/
/***** Depth Testing Functions *****/
/**********************************************************************/
/*
* Depth test horizontal spans of fragments. These functions are called
* via ctx->Driver.depth_test_span only.
*
* Input: n - number of pixels in the span
* x, y - location of leftmost pixel in span in window coords
* z - array [n] of integer depth values
* In/Out: mask - array [n] of flags (1=draw pixel, 0=don't draw)
* Return: number of pixels which passed depth test
*/
/*
* glDepthFunc( any ) and glDepthMask( GL_TRUE or GL_FALSE ).
*/
GLuint gl_depth_test_span_generic( GLcontext* ctx,
GLuint n, GLint x, GLint y,
const GLdepth z[],
GLubyte mask[] )
{
GLdepth *zptr = Z_ADDRESS( ctx, x, y );
GLubyte *m = mask;
GLuint i;
GLuint passed = 0;
/* switch cases ordered from most frequent to less frequent */
switch (ctx->Depth.Func) {
case GL_LESS:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++,zptr++,m++) {
if (*m) {
if (z[i] < *zptr) {
/* pass */
*zptr = z[i];
passed++;
}
else {
/* fail */
*m = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++,zptr++,m++) {
if (*m) {
if (z[i] < *zptr) {
/* pass */
passed++;
}
else {
*m = 0;
}
}
}
}
break;
case GL_LEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] <= *zptr) {
*zptr = z[i];
passed++;
}
else {
*m = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] <= *zptr) {
/* pass */
passed++;
}
else {
*m = 0;
}
}
}
}
break;
case GL_GEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] >= *zptr) {
*zptr = z[i];
passed++;
}
else {
*m = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] >= *zptr) {
/* pass */
passed++;
}
else {
*m = 0;
}
}
}
}
break;
case GL_GREATER:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] > *zptr) {
*zptr = z[i];
passed++;
}
else {
*m = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] > *zptr) {
/* pass */
passed++;
}
else {
*m = 0;
}
}
}
}
break;
case GL_NOTEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] != *zptr) {
*zptr = z[i];
passed++;
}
else {
*m = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] != *zptr) {
/* pass */
passed++;
}
else {
*m = 0;
}
}
}
}
break;
case GL_EQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] == *zptr) {
*zptr = z[i];
passed++;
}
else {
*m =0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
if (z[i] == *zptr) {
/* pass */
passed++;
}
else {
*m =0;
}
}
}
}
break;
case GL_ALWAYS:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0;i<n;i++,zptr++,m++) {
if (*m) {
*zptr = z[i];
passed++;
}
}
}
else {
/* Don't update Z buffer or mask */
passed = n;
}
break;
case GL_NEVER:
for (i=0;i<n;i++) {
mask[i] = 0;
}
break;
default:
abort();
} /*switch*/
return passed;
}
/*
* glDepthFunc(GL_LESS) and glDepthMask(GL_TRUE).
*/
GLuint gl_depth_test_span_less( GLcontext* ctx,
GLuint n, GLint x, GLint y, const GLdepth z[],
GLubyte mask[] )
{
GLdepth *zptr = Z_ADDRESS( ctx, x, y );
GLuint i;
GLuint passed = 0;
for (i=0; i<n; i++) {
if (mask[i]) {
if (z[i] < zptr[i]) {
/* pass */
zptr[i] = z[i];
passed++;
}
else {
/* fail */
mask[i] = 0;
}
}
}
return passed;
}
/*
* glDepthFunc(GL_GREATER) and glDepthMask(GL_TRUE).
*/
GLuint gl_depth_test_span_greater( GLcontext* ctx,
GLuint n, GLint x, GLint y,
const GLdepth z[],
GLubyte mask[] )
{
GLdepth *zptr = Z_ADDRESS( ctx, x, y );
GLuint i;
GLuint passed = 0;
for (i=0; i<n; i++) {
if (mask[i]) {
if (z[i] > zptr[i]) {
/* pass */
zptr[i] = z[i];
passed++;
}
else {
/* fail */
mask[i] = 0;
}
}
}
return passed;
}
/*
* Depth test an array of randomly positioned fragments.
*/
#define ZADDR_SETUP GLdepth *depthbuffer = ctx->Buffer->Depth; \
GLint width = ctx->Buffer->Width;
#define ZADDR( X, Y ) (depthbuffer + (Y) * width + (X) )
/*
* glDepthFunc( any ) and glDepthMask( GL_TRUE or GL_FALSE ).
*/
void gl_depth_test_pixels_generic( GLcontext* ctx,
GLuint n, const GLint x[], const GLint y[],
const GLdepth z[], GLubyte mask[] )
{
register GLdepth *zptr;
register GLuint i;
/* switch cases ordered from most frequent to less frequent */
switch (ctx->Depth.Func) {
case GL_LESS:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] < *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] < *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_LEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] <= *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] <= *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_GEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] >= *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] >= *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_GREATER:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] > *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] > *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_NOTEQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] != *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] != *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_EQUAL:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] == *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
else {
/* Don't update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] == *zptr) {
/* pass */
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
break;
case GL_ALWAYS:
if (ctx->Depth.Mask) {
/* Update Z buffer */
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
*zptr = z[i];
}
}
}
else {
/* Don't update Z buffer or mask */
}
break;
case GL_NEVER:
/* depth test never passes */
for (i=0;i<n;i++) {
mask[i] = 0;
}
break;
default:
abort();
} /*switch*/
}
/*
* glDepthFunc( GL_LESS ) and glDepthMask( GL_TRUE ).
*/
void gl_depth_test_pixels_less( GLcontext* ctx,
GLuint n, const GLint x[], const GLint y[],
const GLdepth z[], GLubyte mask[] )
{
GLdepth *zptr;
GLuint i;
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] < *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
/*
* glDepthFunc( GL_GREATER ) and glDepthMask( GL_TRUE ).
*/
void gl_depth_test_pixels_greater( GLcontext* ctx,
GLuint n, const GLint x[], const GLint y[],
const GLdepth z[], GLubyte mask[] )
{
GLdepth *zptr;
GLuint i;
for (i=0; i<n; i++) {
if (mask[i]) {
zptr = Z_ADDRESS(ctx,x[i],y[i]);
if (z[i] > *zptr) {
/* pass */
*zptr = z[i];
}
else {
/* fail */
mask[i] = 0;
}
}
}
}
/**********************************************************************/
/***** Read Depth Buffer *****/
/**********************************************************************/
/*
* Return a span of depth values from the depth buffer as floats in [0,1].
* This function is only called through Driver.read_depth_span_float()
* Input: n - how many pixels
* x,y - location of first pixel
* Output: depth - the array of depth values
*/
void gl_read_depth_span_float( GLcontext* ctx,
GLuint n, GLint x, GLint y, GLfloat depth[] )
{
GLdepth *zptr;
GLfloat scale;
GLuint i;
scale = 1.0F / DEPTH_SCALE;
if (ctx->Buffer->Depth) {
zptr = Z_ADDRESS( ctx, x, y );
for (i=0;i<n;i++) {
depth[i] = (GLfloat) zptr[i] * scale;
}
}
else {
for (i=0;i<n;i++) {
depth[i] = 0.0F;
}
}
}
/*
* Return a span of depth values from the depth buffer as integers in
* [0,MAX_DEPTH].
* This function is only called through Driver.read_depth_span_int()
* Input: n - how many pixels
* x,y - location of first pixel
* Output: depth - the array of depth values
*/
void gl_read_depth_span_int( GLcontext* ctx,
GLuint n, GLint x, GLint y, GLdepth depth[] )
{
if (ctx->Buffer->Depth) {
GLdepth *zptr = Z_ADDRESS( ctx, x, y );
MEMCPY( depth, zptr, n * sizeof(GLdepth) );
}
else {
GLuint i;
for (i=0;i<n;i++) {
depth[i] = 0.0;
}
}
}
/**********************************************************************/
/***** Allocate and Clear Depth Buffer *****/
/**********************************************************************/
/*
* Allocate a new depth buffer. If there's already a depth buffer allocated
* it will be free()'d. The new depth buffer will be uniniitalized.
* This function is only called through Driver.alloc_depth_buffer.
*/
void gl_alloc_depth_buffer( GLcontext* ctx )
{
/* deallocate current depth buffer if present */
if (ctx->Buffer->Depth) {
free(ctx->Buffer->Depth);
ctx->Buffer->Depth = NULL;
}
/* allocate new depth buffer */
ctx->Buffer->Depth = (GLdepth *) calloc( ctx->Buffer->Width
* ctx->Buffer->Height,
sizeof(GLdepth) );
if (!ctx->Buffer->Depth) {
/* out of memory */
ctx->Depth.Test = GL_FALSE;
gl_error( ctx, GL_OUT_OF_MEMORY, "Couldn't allocate depth buffer" );
}
}
/*
* Clear the depth buffer. If the depth buffer doesn't exist yet we'll
* allocate it now.
* This function is only called through Driver.clear_depth_buffer.
*/
void gl_clear_depth_buffer( GLcontext* ctx )
{
/* The loops in this function have been written so the IRIX 5.3
* C compiler can unroll them. Hopefully other compilers can too!
*/
if (!ctx->Buffer->Depth) {
gl_alloc_depth_buffer(ctx);
}
if (ctx->Buffer->Depth) {
GLdepth clear_value = (GLdepth) (ctx->Depth.Clear * DEPTH_SCALE);
if (ctx->Scissor.Enabled) {
/* only clear scissor region */
GLint y;
for (y=ctx->Buffer->Ymin; y<=ctx->Buffer->Ymax; y++) {
GLdepth *d = Z_ADDRESS( ctx, ctx->Buffer->Xmin, y );
GLint n = ctx->Buffer->Xmax - ctx->Buffer->Xmin + 1;
do {
*d++ = clear_value;
n--;
} while (n);
}
}
else {
/* clear whole buffer */
if (sizeof(GLdepth)==2 && (clear_value&0xff)==(clear_value>>8)) {
/* lower and upper bytes of clear_value are same, use MEMSET */
MEMSET( ctx->Buffer->Depth, clear_value&0xff,
2*ctx->Buffer->Width*ctx->Buffer->Height);
}
else {
GLdepth *d = ctx->Buffer->Depth;
GLint n = ctx->Buffer->Width * ctx->Buffer->Height;
while (n>=16) {
d[0] = clear_value; d[1] = clear_value;
d[2] = clear_value; d[3] = clear_value;
d[4] = clear_value; d[5] = clear_value;
d[6] = clear_value; d[7] = clear_value;
d[8] = clear_value; d[9] = clear_value;
d[10] = clear_value; d[11] = clear_value;
d[12] = clear_value; d[13] = clear_value;
d[14] = clear_value; d[15] = clear_value;
d += 16;
n -= 16;
}
while (n>0) {
*d++ = clear_value;
n--;
}
}
}
}
}
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