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/* $Id: depth.c,v 1.10 1997/05/28 03:24:22 brianp Exp $ */ /* * Mesa 3-D graphics library * Version: 2.3 * Copyright (C) 1995-1997 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 1.10 1997/05/28 03:24:22 brianp * added precompiled header (PCH) support * * Revision 1.9 1997/04/20 19:54:15 brianp * replaced abort() with gl_problem() * * Revision 1.8 1997/02/27 19:58:52 brianp * don't try to clear depth buffer if there isn't one * * Revision 1.7 1997/01/31 23:33:08 brianp * replaced calloc with malloc in gl_alloc_depth_buffer() * * Revision 1.6 1996/11/04 01:42:07 brianp * multiply Viewport.Sz and .Tz by DEPTH_SCALE * * 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 */ #ifdef PCH #include "all.h" #else #include <stdlib.h> #include <string.h> #include "context.h" #include "depth.h" #include "dlist.h" #include "macros.h" #include "types.h" #endif /**********************************************************************/ /***** 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 = DEPTH_SCALE * ((f - n) / 2.0); ctx->Viewport.Tz = DEPTH_SCALE * ((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: gl_problem(ctx, "Bad depth func in gl_depth_test_span_generic"); } /*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: gl_problem(ctx, "Bad depth func in gl_depth_test_pixels_generic"); } /*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, but don't initialize it */ ctx->Buffer->Depth = (GLdepth *) malloc( 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 ) { GLdepth clear_value = (GLdepth) (ctx->Depth.Clear * DEPTH_SCALE); if (ctx->Visual->DepthBits==0 || !ctx->Buffer->Depth) { /* no depth buffer */ return; } /* 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->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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