osmesa.c

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

   DST[BCOMP] = SRC[2];  \
   DST[ACOMP] = 1.0F
#include "swrast/s_spantemp.h"


/* 8-bit BGR */
#define NAME(PREFIX) PREFIX##_BGR8
#define RB_TYPE GLubyte
#define SPAN_VARS \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define INIT_PIXEL_PTR(P, X, Y) \
   GLubyte *P = (GLubyte *) osmesa->rowaddr[Y] + 3 * (X)
#define INC_PIXEL_PTR(P) P += 3
#define STORE_PIXEL(DST, X, Y, VALUE) \
   DST[2] = VALUE[RCOMP];  \
   DST[1] = VALUE[GCOMP];  \
   DST[0] = VALUE[BCOMP]
#define FETCH_PIXEL(DST, SRC) \
   DST[RCOMP] = SRC[2];  \
   DST[GCOMP] = SRC[1];  \
   DST[BCOMP] = SRC[0];  \
   DST[ACOMP] = 255
#include "swrast/s_spantemp.h"

/* 16-bit BGR */
#define NAME(PREFIX) PREFIX##_BGR16
#define RB_TYPE GLushort
#define SPAN_VARS \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define INIT_PIXEL_PTR(P, X, Y) \
   GLushort *P = (GLushort *) osmesa->rowaddr[Y] + 3 * (X)
#define INC_PIXEL_PTR(P) P += 3
#define STORE_PIXEL(DST, X, Y, VALUE) \
   DST[2] = VALUE[RCOMP];  \
   DST[1] = VALUE[GCOMP];  \
   DST[0] = VALUE[BCOMP]
#define FETCH_PIXEL(DST, SRC) \
   DST[RCOMP] = SRC[2];  \
   DST[GCOMP] = SRC[1];  \
   DST[BCOMP] = SRC[0];  \
   DST[ACOMP] = 65535
#include "swrast/s_spantemp.h"

/* 32-bit BGR */
#define NAME(PREFIX) PREFIX##_BGR32
#define RB_TYPE GLfloat
#define SPAN_VARS \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define INIT_PIXEL_PTR(P, X, Y) \
   GLfloat *P = (GLfloat *) osmesa->rowaddr[Y] + 3 * (X)
#define INC_PIXEL_PTR(P) P += 3
#define STORE_PIXEL(DST, X, Y, VALUE) \
   DST[2] = VALUE[RCOMP];  \
   DST[1] = VALUE[GCOMP];  \
   DST[0] = VALUE[BCOMP]
#define FETCH_PIXEL(DST, SRC) \
   DST[RCOMP] = SRC[2];  \
   DST[GCOMP] = SRC[1];  \
   DST[BCOMP] = SRC[0];  \
   DST[ACOMP] = 1.0F
#include "swrast/s_spantemp.h"


/* 16-bit 5/6/5 RGB */
#define NAME(PREFIX) PREFIX##_RGB_565
#define RB_TYPE GLubyte
#define SPAN_VARS \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define INIT_PIXEL_PTR(P, X, Y) \
   GLushort *P = (GLushort *) osmesa->rowaddr[Y] + (X)
#define INC_PIXEL_PTR(P) P += 1
#define STORE_PIXEL(DST, X, Y, VALUE) \
   *DST = ( (((VALUE[RCOMP]) & 0xf8) << 8) | (((VALUE[GCOMP]) & 0xfc) << 3) | ((VALUE[BCOMP]) >> 3) )
#define FETCH_PIXEL(DST, SRC) \
   DST[RCOMP] = ( (((*SRC) >> 8) & 0xf8) | (((*SRC) >> 11) & 0x7) ); \
   DST[GCOMP] = ( (((*SRC) >> 3) & 0xfc) | (((*SRC) >>  5) & 0x3) ); \
   DST[BCOMP] = ( (((*SRC) << 3) & 0xf8) | (((*SRC)      ) & 0x7) ); \
   DST[ACOMP] = CHAN_MAX
#include "swrast/s_spantemp.h"


/* color index */
#define NAME(PREFIX) PREFIX##_CI
#define CI_MODE
#define RB_TYPE GLubyte
#define SPAN_VARS \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define INIT_PIXEL_PTR(P, X, Y) \
   GLubyte *P = (GLubyte *) osmesa->rowaddr[Y] + (X)
#define INC_PIXEL_PTR(P) P += 1
#define STORE_PIXEL(DST, X, Y, VALUE) \
   *DST = VALUE[0]
#define FETCH_PIXEL(DST, SRC) \
   DST = SRC[0]
#include "swrast/s_spantemp.h"




/**
 * Macros for optimized line/triangle rendering.
 * Only for 8-bit channel, RGBA, BGRA, ARGB formats.
 */

#define PACK_RGBA(DST, R, G, B, A)	\
do {					\
   (DST)[osmesa->rInd] = R;		\
   (DST)[osmesa->gInd] = G;		\
   (DST)[osmesa->bInd] = B;		\
   (DST)[osmesa->aInd] = A;		\
} while (0)

#define PIXELADDR4(X,Y)  ((GLchan *) osmesa->rowaddr[Y] + 4 * (X))


/**
 * Draw a flat-shaded, RGB line into an osmesa buffer.
 */
#define NAME flat_rgba_line
#define CLIP_HACK 1
#define SETUP_CODE						\
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);		\
   const GLchan *color = vert1->color;

#define PLOT(X, Y)						\
do {								\
   GLchan *p = PIXELADDR4(X, Y);				\
   PACK_RGBA(p, color[0], color[1], color[2], color[3]);	\
} while (0)

#ifdef WIN32
#include "..\swrast\s_linetemp.h"
#else
#include "swrast/s_linetemp.h"
#endif



/**
 * Draw a flat-shaded, Z-less, RGB line into an osmesa buffer.
 */
#define NAME flat_rgba_z_line
#define CLIP_HACK 1
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define SETUP_CODE					\
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);	\
   const GLchan *color = vert1->color;

#define PLOT(X, Y)					\
do {							\
   if (Z < *zPtr) {					\
      GLchan *p = PIXELADDR4(X, Y);			\
      PACK_RGBA(p, color[RCOMP], color[GCOMP],		\
                   color[BCOMP], color[ACOMP]);		\
      *zPtr = Z;					\
   }							\
} while (0)

#ifdef WIN32
#include "..\swrast\s_linetemp.h"
#else
#include "swrast/s_linetemp.h"
#endif



/**
 * Analyze context state to see if we can provide a fast line drawing
 * function.  Otherwise, return NULL.
 */
static swrast_line_func
osmesa_choose_line_function( GLcontext *ctx )
{
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
   const SWcontext *swrast = SWRAST_CONTEXT(ctx);

   if (osmesa->rb->DataType != GL_UNSIGNED_BYTE)
      return NULL;

   if (ctx->RenderMode != GL_RENDER)      return NULL;
   if (ctx->Line.SmoothFlag)              return NULL;
   if (ctx->Texture._EnabledUnits)        return NULL;
   if (ctx->Light.ShadeModel != GL_FLAT)  return NULL;
   if (ctx->Line.Width != 1.0F)           return NULL;
   if (ctx->Line.StippleFlag)             return NULL;
   if (ctx->Line.SmoothFlag)              return NULL;
   if (osmesa->format != OSMESA_RGBA &&
       osmesa->format != OSMESA_BGRA &&
       osmesa->format != OSMESA_ARGB)     return NULL;

   if (swrast->_RasterMask==DEPTH_BIT
       && ctx->Depth.Func==GL_LESS
       && ctx->Depth.Mask==GL_TRUE
       && ctx->Visual.depthBits == DEFAULT_SOFTWARE_DEPTH_BITS) {
      return (swrast_line_func) flat_rgba_z_line;
   }

   if (swrast->_RasterMask == 0) {
      return (swrast_line_func) flat_rgba_line;
   }

   return (swrast_line_func) NULL;
}


/**********************************************************************/
/*****                 Optimized triangle rendering               *****/
/**********************************************************************/


/*
 * Smooth-shaded, z-less triangle, RGBA color.
 */
#define NAME smooth_rgba_z_triangle
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define INTERP_RGB 1
#define INTERP_ALPHA 1
#define SETUP_CODE \
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
#define RENDER_SPAN( span ) {					\
   GLuint i;							\
   GLchan *img = PIXELADDR4(span.x, span.y); 			\
   for (i = 0; i < span.end; i++, img += 4) {			\
      const GLuint z = FixedToDepth(span.z);			\
      if (z < zRow[i]) {					\
         PACK_RGBA(img, FixedToChan(span.red),			\
            FixedToChan(span.green), FixedToChan(span.blue),	\
            FixedToChan(span.alpha));				\
         zRow[i] = z;						\
      }								\
      span.red += span.redStep;					\
      span.green += span.greenStep;				\
      span.blue += span.blueStep;				\
      span.alpha += span.alphaStep;				\
      span.z += span.zStep;					\
   }                                                            \
}
#ifdef WIN32
#include "..\swrast\s_tritemp.h"
#else
#include "swrast/s_tritemp.h"
#endif



/*
 * Flat-shaded, z-less triangle, RGBA color.
 */
#define NAME flat_rgba_z_triangle
#define INTERP_Z 1
#define DEPTH_TYPE DEFAULT_SOFTWARE_DEPTH_TYPE
#define SETUP_CODE						\
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);		\
   GLuint pixel;						\
   PACK_RGBA((GLchan *) &pixel, v2->color[0], v2->color[1],	\
                                v2->color[2], v2->color[3]);

#define RENDER_SPAN( span ) {				\
   GLuint i;						\
   GLuint *img = (GLuint *) PIXELADDR4(span.x, span.y);	\
   for (i = 0; i < span.end; i++) {			\
      const GLuint z = FixedToDepth(span.z);		\
      if (z < zRow[i]) {				\
         img[i] = pixel;				\
         zRow[i] = z;					\
      }							\
      span.z += span.zStep;				\
   }                                                    \
}
#ifdef WIN32
#include "..\swrast\s_tritemp.h"
#else
#include "swrast/s_tritemp.h"
#endif



/**
 * Return pointer to an optimized triangle function if possible.
 */
static swrast_tri_func
osmesa_choose_triangle_function( GLcontext *ctx )
{
   const OSMesaContext osmesa = OSMESA_CONTEXT(ctx);
   const SWcontext *swrast = SWRAST_CONTEXT(ctx);

   if (osmesa->rb->DataType != GL_UNSIGNED_BYTE)
      return (swrast_tri_func) NULL;

   if (ctx->RenderMode != GL_RENDER)    return (swrast_tri_func) NULL;
   if (ctx->Polygon.SmoothFlag)         return (swrast_tri_func) NULL;
   if (ctx->Polygon.StippleFlag)        return (swrast_tri_func) NULL;
   if (ctx->Texture._EnabledUnits)      return (swrast_tri_func) NULL;
   if (osmesa->format != OSMESA_RGBA &&
       osmesa->format != OSMESA_BGRA &&
       osmesa->format != OSMESA_ARGB)   return (swrast_tri_func) NULL;
   if (ctx->Polygon.CullFlag && 
       ctx->Polygon.CullFaceMode == GL_FRONT_AND_BACK)
                                        return (swrast_tri_func) NULL;

   if (swrast->_RasterMask == DEPTH_BIT &&
       ctx->Depth.Func == GL_LESS &&
       ctx->Depth.Mask == GL_TRUE &&
       ctx->Visual.depthBits == DEFAULT_SOFTWARE_DEPTH_BITS) {
      if (ctx->Light.ShadeModel == GL_SMOOTH) {
         return (swrast_tri_func) smooth_rgba_z_triangle;
      }
      else {
         return (swrast_tri_func) flat_rgba_z_triangle;
      }
   }
   return (swrast_tri_func) NULL;
}



/* Override for the swrast triangle-selection function.  Try to use one
 * of our internal triangle functions, otherwise fall back to the
 * standard swrast functions.
 */
static void
osmesa_choose_triangle( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   swrast->Triangle = osmesa_choose_triangle_function( ctx );
   if (!swrast->Triangle)
      _swrast_choose_triangle( ctx );
}

static void
osmesa_choose_line( GLcontext *ctx )
{
   SWcontext *swrast = SWRAST_CONTEXT(ctx);

   swrast->Line = osmesa_choose_line_function( ctx );
   if (!swrast->Line)
      _swrast_choose_line( ctx );
}



/**
 * Recompute the values of the context's rowaddr array.
 */
static void
compute_row_addresses( OSMesaContext osmesa )
{
   GLint bytesPerPixel, bytesPerRow, i;
   GLubyte *origin = (GLubyte *) osmesa->rb->Data;
   GLint bpc; /* bytes per channel */
   GLint rowlength; /* in pixels */
   GLint height = osmesa->rb->Height;

   if (osmesa->userRowLength)
      rowlength = osmesa->userRowLength;
   else
      rowlength = osmesa->rb->Width;

   if (osmesa->rb->DataType == GL_UNSIGNED_BYTE)
      bpc = 1;
   else if (osmesa->rb->DataType == GL_UNSIGNED_SHORT)
      bpc = 2;
   else if (osmesa->rb->DataType == GL_FLOAT)
      bpc = 4;
   else {
      _mesa_problem(&osmesa->mesa,
                    "Unexpected datatype in osmesa::compute_row_addresses");
      return;
   }

   if (osmesa->format == OSMESA_COLOR_INDEX) {
      /* CI mode */
      bytesPerPixel = 1 * sizeof(GLubyte);
   }
   else if ((osmesa->format == OSMESA_RGB) || (osmesa->format == OSMESA_BGR)) {
      /* RGB mode */
      bytesPerPixel = 3 * bpc;
   }
   else if (osmesa->format == OSMESA_RGB_565) {
      /* 5/6/5 RGB pixel in 16 bits */
      bytesPerPixel = 2;
   }
   else {
      /* RGBA mode */
      bytesPerPixel = 4 * bpc;
   }

   bytesPerRow = rowlength * bytesPerPixel;

   if (osmesa->yup) {
      /* Y=0 is bottom line of window */
      for (i = 0; i < height; i++) {
         osmesa->rowaddr[i] = (GLvoid *) ((GLubyte *) origin + i * bytesPerRow);
      }
   }
   else {
      /* Y=0 is top line of window */
      for (i = 0; i < height; i++) {
         GLint j = height - i - 1;
         osmesa->rowaddr[i] = (GLvoid *) ((GLubyte *) origin + j * bytesPerRow);