mesa: rewrite accum buffer support

Implemented in terms of renderbuffer mapping/unmapping and format
packing/unpacking functions.

The swrast and state tracker code for implementing accumulation are
unused and will be removed in the next commit.

v2: don't use memcpy() in _mesa_clear_accum_buffer()
v3: don't allocate MAX_WIDTH arrays, be more careful with mapping flags

Reviewed-by: Eric Anholt <eric@anholt.net>

src/mesa/SConscript

@@ -153,7 +153,6 @@ math_sources = [
 swrast_sources = [
     'swrast/s_aaline.c',
     'swrast/s_aatriangle.c',
-    'swrast/s_accum.c',
     'swrast/s_alpha.c',
     'swrast/s_atifragshader.c',
     'swrast/s_bitmap.c',
@@ -241,7 +240,6 @@ statetracker_sources = [
     'state_tracker/st_atom_stipple.c',
     'state_tracker/st_atom_texture.c',
     'state_tracker/st_atom_viewport.c',
-    'state_tracker/st_cb_accum.c',
     'state_tracker/st_cb_bitmap.c',
     'state_tracker/st_cb_blit.c',
     'state_tracker/st_cb_bufferobjects.c',

src/mesa/drivers/common/driverfuncs.c

@@ -25,6 +25,7 @@
 
 #include "main/glheader.h"
 #include "main/imports.h"
+#include "main/accum.h"
 #include "main/arrayobj.h"
 #include "main/context.h"
 #include "main/framebuffer.h"
@@ -80,7 +81,7 @@ _mesa_init_driver_functions(struct dd_function_table *driver)
 
    /* framebuffer/image functions */
    driver->Clear = _swrast_Clear;
-   driver->Accum = _swrast_Accum;
+   driver->Accum = _mesa_accum;
    driver->RasterPos = _tnl_RasterPos;
    driver->DrawPixels = _swrast_DrawPixels;
    driver->ReadPixels = _mesa_readpixels;

src/mesa/drivers/dri/intel/intel_pixel.c

@@ -157,7 +157,7 @@ intel_check_blit_format(struct intel_region * region,
 void
 intelInitPixelFuncs(struct dd_function_table *functions)
 {
-   functions->Accum = _swrast_Accum;
+   functions->Accum = _mesa_accum;
    if (!getenv("INTEL_NO_BLIT")) {
       functions->Bitmap = intelBitmap;
       functions->CopyPixels = intelCopyPixels;

src/mesa/main/accum.c

@@ -24,7 +24,10 @@
 
 #include "glheader.h"
 #include "accum.h"
+#include "condrender.h"
 #include "context.h"
+#include "format_unpack.h"
+#include "format_pack.h"
 #include "imports.h"
 #include "macros.h"
 #include "mfeatures.h"
@@ -101,7 +104,7 @@ _mesa_Accum( GLenum op, GLfloat value )
       return;
 
    if (ctx->RenderMode == GL_RENDER) {
-      ctx->Driver.Accum(ctx, op, value);
+      _mesa_accum(ctx, op, value);
    }
 }
 
@@ -123,3 +126,384 @@ _mesa_init_accum( struct gl_context *ctx )
    /* Accumulate buffer group */
    ASSIGN_4V( ctx->Accum.ClearColor, 0.0, 0.0, 0.0, 0.0 );
 }
+
+
+
+
+/**
+ * Clear the accumulation buffer by mapping the renderbuffer and
+ * writing the clear color to it.  Called by the driver's implementation
+ * of the glClear function.
+ */
+void
+_mesa_clear_accum_buffer(struct gl_context *ctx)
+{
+   GLuint x, y, width, height;
+   GLubyte *accMap;
+   GLint accRowStride;
+   struct gl_renderbuffer *accRb;
+
+   if (!ctx->DrawBuffer)
+      return;
+
+   accRb = ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
+   if (!accRb)
+      return;   /* missing accum buffer, not an error */
+
+   /* bounds, with scissor */
+   x = ctx->DrawBuffer->_Xmin;
+   y = ctx->DrawBuffer->_Ymin;
+   width = ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
+   height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
+
+   ctx->Driver.MapRenderbuffer(ctx, accRb, x, y, width, height,
+                               GL_MAP_WRITE_BIT, &accMap, &accRowStride);
+
+   if (!accMap) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      return;
+   }
+
+   if (accRb->Format == MESA_FORMAT_SIGNED_RGBA_16) {
+      const GLshort clearR = FLOAT_TO_SHORT(ctx->Accum.ClearColor[0]);
+      const GLshort clearG = FLOAT_TO_SHORT(ctx->Accum.ClearColor[1]);
+      const GLshort clearB = FLOAT_TO_SHORT(ctx->Accum.ClearColor[2]);
+      const GLshort clearA = FLOAT_TO_SHORT(ctx->Accum.ClearColor[3]);
+      GLuint i, j;
+
+      for (j = 0; j < height; j++) {
+         GLshort *row = (GLshort *) accMap;
+         
+         for (i = 0; i < width; i++) {
+            row[i * 4 + 0] = clearR;
+            row[i * 4 + 1] = clearG;
+            row[i * 4 + 2] = clearB;
+            row[i * 4 + 3] = clearA;
+         }
+         accMap += accRowStride;
+      }
+   }
+   else {
+      /* other types someday? */
+      _mesa_warning(ctx, "unexpected accum buffer type");
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
+}
+
+
+/**
+ * if (bias)
+ *    Accum += value
+ * else
+ *    Accum *= value
+ */
+static void
+accum_scale_or_bias(struct gl_context *ctx, GLfloat value,
+                    GLint xpos, GLint ypos, GLint width, GLint height,
+                    GLboolean bias)
+{
+   struct gl_renderbuffer *accRb =
+      ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
+   GLubyte *accMap;
+   GLint accRowStride;
+
+   assert(accRb);
+
+   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
+                               GL_MAP_READ_BIT | GL_MAP_WRITE_BIT,
+                               &accMap, &accRowStride);
+
+   if (!accMap) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      return;
+   }
+
+   if (accRb->Format == MESA_FORMAT_SIGNED_RGBA_16) {
+      const GLshort incr = (GLshort) (value * 32767.0f);
+      GLuint i, j;
+      if (bias) {
+         for (j = 0; j < height; j++) {
+            GLshort *acc = (GLshort *) accMap;
+            for (i = 0; i < 4 * width; i++) {
+               acc[i] += incr;
+            }
+            accMap += accRowStride;
+         }
+      }
+      else {
+         /* scale */
+         for (j = 0; j < height; j++) {
+            GLshort *acc = (GLshort *) accMap;
+            for (i = 0; i < 4 * width; i++) {
+               acc[i] = (GLshort) (acc[i] * value);
+            }
+            accMap += accRowStride;
+         }
+      }
+   }
+   else {
+      /* other types someday? */
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
+}
+
+
+/**
+ * if (load)
+ *    Accum = ColorBuf * value
+ * else
+ *    Accum += ColorBuf * value
+ */
+static void
+accum_or_load(struct gl_context *ctx, GLfloat value,
+              GLint xpos, GLint ypos, GLint width, GLint height,
+              GLboolean load)
+{
+   struct gl_renderbuffer *accRb =
+      ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer;
+   struct gl_renderbuffer *colorRb = ctx->ReadBuffer->_ColorReadBuffer;
+   GLubyte *accMap, *colorMap;
+   GLint accRowStride, colorRowStride;
+   GLbitfield mappingFlags;
+
+   if (!colorRb) {
+      /* no read buffer - OK */
+      return;
+   }
+
+   assert(accRb);
+
+   mappingFlags = GL_MAP_WRITE_BIT;
+   if (!load) /* if we're accumulating */
+      mappingFlags |= GL_MAP_READ_BIT;
+
+   /* Map accum buffer */
+   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
+                               mappingFlags, &accMap, &accRowStride);
+   if (!accMap) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      return;
+   }
+
+   /* Map color buffer */
+   ctx->Driver.MapRenderbuffer(ctx, colorRb, xpos, ypos, width, height,
+                               GL_MAP_READ_BIT,
+                               &colorMap, &colorRowStride);
+   if (!colorMap) {
+      ctx->Driver.UnmapRenderbuffer(ctx, accRb);
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      return;
+   }
+
+   if (accRb->Format == MESA_FORMAT_SIGNED_RGBA_16) {
+      const GLfloat scale = value * 32767.0f;
+      GLuint i, j;
+      GLfloat (*rgba)[4];
+
+      rgba = (GLfloat (*)[4]) malloc(width * 4 * sizeof(GLfloat));
+      if (rgba) {
+         for (j = 0; j < height; j++) {
+            GLshort *acc = (GLshort *) accMap;
+
+            /* read colors from source color buffer */
+            _mesa_unpack_rgba_row(colorRb->Format, width, colorMap, rgba);
+
+            if (load) {
+               for (i = 0; i < width; i++) {
+                  acc[i * 4 + 0] = (GLshort) (rgba[i][RCOMP] * scale);
+                  acc[i * 4 + 1] = (GLshort) (rgba[i][GCOMP] * scale);
+                  acc[i * 4 + 2] = (GLshort) (rgba[i][BCOMP] * scale);
+                  acc[i * 4 + 3] = (GLshort) (rgba[i][ACOMP] * scale);
+               }
+            }
+            else {
+               /* accumulate */
+               for (i = 0; i < width; i++) {
+                  acc[i * 4 + 0] += (GLshort) (rgba[i][RCOMP] * scale);
+                  acc[i * 4 + 1] += (GLshort) (rgba[i][GCOMP] * scale);
+                  acc[i * 4 + 2] += (GLshort) (rgba[i][BCOMP] * scale);
+                  acc[i * 4 + 3] += (GLshort) (rgba[i][ACOMP] * scale);
+               }
+            }
+
+            colorMap += colorRowStride;
+            accMap += accRowStride;
+         }
+
+         free(rgba);
+      }
+      else {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      }
+   }
+   else {
+      /* other types someday? */
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
+   ctx->Driver.UnmapRenderbuffer(ctx, colorRb);
+}
+
+
+/**
+ * ColorBuffer = Accum * value
+ */
+static void
+accum_return(struct gl_context *ctx, GLfloat value,
+             GLint xpos, GLint ypos, GLint width, GLint height)
+{
+   struct gl_framebuffer *fb = ctx->DrawBuffer;
+   struct gl_renderbuffer *accRb = fb->Attachment[BUFFER_ACCUM].Renderbuffer;
+   GLubyte *accMap, *colorMap;
+   GLint accRowStride, colorRowStride;
+   GLuint buffer;
+
+   /* Map accum buffer */
+   ctx->Driver.MapRenderbuffer(ctx, accRb, xpos, ypos, width, height,
+                               GL_MAP_READ_BIT,
+                               &accMap, &accRowStride);
+   if (!accMap) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+      return;
+   }
+
+   /* Loop over destination buffers */
+   for (buffer = 0; buffer < fb->_NumColorDrawBuffers; buffer++) {
+      struct gl_renderbuffer *colorRb = fb->_ColorDrawBuffers[buffer];
+      const GLboolean masking = (!ctx->Color.ColorMask[buffer][RCOMP] ||
+                                 !ctx->Color.ColorMask[buffer][GCOMP] ||
+                                 !ctx->Color.ColorMask[buffer][BCOMP] ||
+                                 !ctx->Color.ColorMask[buffer][ACOMP]);
+      GLbitfield mappingFlags = GL_MAP_WRITE_BIT;
+
+      if (masking)
+         mappingFlags |= GL_MAP_READ_BIT;
+
+      /* Map color buffer */
+      ctx->Driver.MapRenderbuffer(ctx, colorRb, xpos, ypos, width, height,
+                                  mappingFlags, &colorMap, &colorRowStride);
+      if (!colorMap) {
+         _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+         continue;
+      }
+
+      if (accRb->Format == MESA_FORMAT_SIGNED_RGBA_16) {
+         const GLfloat scale = value / 32767.0f;
+         GLint i, j;
+         GLfloat (*rgba)[4], (*dest)[4];
+
+         rgba = (GLfloat (*)[4]) malloc(width * 4 * sizeof(GLfloat));
+         dest = (GLfloat (*)[4]) malloc(width * 4 * sizeof(GLfloat));
+
+         if (rgba && dest) {
+            for (j = 0; j < height; j++) {
+               GLshort *acc = (GLshort *) accMap;
+
+               for (i = 0; i < width; i++) {
+                  rgba[i][0] = acc[i * 4 + 0] * scale;
+                  rgba[i][1] = acc[i * 4 + 1] * scale;
+                  rgba[i][2] = acc[i * 4 + 2] * scale;
+                  rgba[i][3] = acc[i * 4 + 3] * scale;
+               }
+
+               if (masking) {
+
+                  /* get existing colors from dest buffer */
+                  _mesa_unpack_rgba_row(colorRb->Format, width, colorMap, dest);
+
+                  /* use the dest colors where mask[channel] = 0 */
+                  if (ctx->Color.ColorMask[buffer][RCOMP] == 0) {
+                     for (i = 0; i < width; i++)
+                        rgba[i][RCOMP] = dest[i][RCOMP];
+                  }
+                  if (ctx->Color.ColorMask[buffer][GCOMP] == 0) {
+                     for (i = 0; i < width; i++)
+                        rgba[i][GCOMP] = dest[i][GCOMP];
+                  }
+                  if (ctx->Color.ColorMask[buffer][BCOMP] == 0) {
+                     for (i = 0; i < width; i++)
+                        rgba[i][BCOMP] = dest[i][BCOMP];
+                  }
+                  if (ctx->Color.ColorMask[buffer][ACOMP] == 0) {
+                     for (i = 0; i < width; i++)
+                        rgba[i][ACOMP] = dest[i][ACOMP];
+                  }
+               }
+
+               _mesa_pack_float_rgba_row(colorRb->Format, width,
+                                         (const GLfloat (*)[4]) rgba, colorMap);
+
+               accMap += accRowStride;
+               colorMap += colorRowStride;
+            }
+         }
+         else {
+            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAccum");
+         }
+         free(rgba);
+         free(dest);
+      }
+      else {
+         /* other types someday? */
+      }
+
+      ctx->Driver.UnmapRenderbuffer(ctx, colorRb);
+   }
+
+   ctx->Driver.UnmapRenderbuffer(ctx, accRb);
+}
+
+
+
+/**
+ * Software fallback for glAccum.  A hardware driver that supports
+ * signed 16-bit color channels could implement hardware accumulation
+ * operations, but no driver does so at this time.
+ */
+void
+_mesa_accum(struct gl_context *ctx, GLenum op, GLfloat value)
+{
+   GLint xpos, ypos, width, height;
+
+   if (!ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer) {
+      _mesa_warning(ctx, "Calling glAccum() without an accumulation buffer");
+      return;
+   }
+
+   if (!_mesa_check_conditional_render(ctx))
+      return;
+
+   xpos = ctx->DrawBuffer->_Xmin;
+   ypos = ctx->DrawBuffer->_Ymin;
+   width =  ctx->DrawBuffer->_Xmax - ctx->DrawBuffer->_Xmin;
+   height = ctx->DrawBuffer->_Ymax - ctx->DrawBuffer->_Ymin;
+
+   switch (op) {
+   case GL_ADD:
+      if (value != 0.0F) {
+         accum_scale_or_bias(ctx, value, xpos, ypos, width, height, GL_TRUE);
+      }
+      break;
+   case GL_MULT:
+      if (value != 1.0F) {
+         accum_scale_or_bias(ctx, value, xpos, ypos, width, height, GL_FALSE);
+      }
+      break;
+   case GL_ACCUM:
+      if (value != 0.0F) {
+         accum_or_load(ctx, value, xpos, ypos, width, height, GL_FALSE);
+      }
+      break;
+   case GL_LOAD:
+      accum_or_load(ctx, value, xpos, ypos, width, height, GL_TRUE);
+      break;
+   case GL_RETURN:
+      accum_return(ctx, value, xpos, ypos, width, height);
+      break;
+   default:
+      _mesa_problem(ctx, "invalid mode in _mesa_accum()");
+      break;
+   }
+}

src/mesa/main/accum.h

@@ -42,6 +42,7 @@
 
 struct _glapi_table;
 struct gl_context;
+struct gl_renderbuffer;
 
 #if FEATURE_accum
 
@@ -51,6 +52,12 @@ _mesa_ClearAccum( GLfloat red, GLfloat green, GLfloat blue, GLfloat alpha );
 extern void
 _mesa_init_accum_dispatch(struct _glapi_table *disp);
 
+extern void
+_mesa_accum(struct gl_context *ctx, GLenum op, GLfloat value);
+
+extern void
+_mesa_clear_accum_buffer(struct gl_context *ctx);
+
 #else /* FEATURE_accum */
 
 #include "main/compiler.h"
@@ -67,6 +74,17 @@ _mesa_init_accum_dispatch(struct _glapi_table *disp)
 {
 }
 
+static inline void
+_mesa_accum(struct gl_context *ctx, GLenum op, GLfloat value)
+{
+}
+
+static inline void
+_mesa_clear_accum_buffer(struct gl_context *ctx)
+{
+}
+
+
 #endif /* FEATURE_accum */
 
 extern void

src/mesa/sources.mak

@@ -125,7 +125,6 @@ MATH_XFORM_SOURCES = \
 SWRAST_SOURCES = \
 	swrast/s_aaline.c \
 	swrast/s_aatriangle.c \
-	swrast/s_accum.c \
 	swrast/s_alpha.c \
 	swrast/s_atifragshader.c \
 	swrast/s_bitmap.c \
@@ -209,7 +208,6 @@ STATETRACKER_SOURCES = \
 	state_tracker/st_atom_stipple.c \
 	state_tracker/st_atom_texture.c \
 	state_tracker/st_atom_viewport.c \
-	state_tracker/st_cb_accum.c \
 	state_tracker/st_cb_bitmap.c \
 	state_tracker/st_cb_blit.c \
 	state_tracker/st_cb_bufferobjects.c \

src/mesa/state_tracker/st_cb_clear.c

@@ -34,12 +34,12 @@
   */
 
 #include "main/glheader.h"
+#include "main/accum.h"
 #include "main/formats.h"
 #include "main/macros.h"
 #include "program/prog_instruction.h"
 #include "st_context.h"
 #include "st_atom.h"
-#include "st_cb_accum.h"
 #include "st_cb_clear.h"
 #include "st_cb_fbo.h"
 #include "st_format.h"
@@ -599,8 +599,7 @@ st_Clear(struct gl_context *ctx, GLbitfield mask)
                       ctx->Depth.Clear, ctx->Stencil.Clear);
    }
    if (mask & BUFFER_BIT_ACCUM)
-      st_clear_accum_buffer(ctx,
-                            ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer);
+      _mesa_clear_accum_buffer(ctx);
 }
 
 

src/mesa/state_tracker/st_cb_fbo.c

@@ -667,6 +667,22 @@ st_MapRenderbuffer(struct gl_context *ctx,
    unsigned usage;
    GLuint y2;
 
+   if (strb->software) {
+      /* software-allocated renderbuffer (probably an accum buffer) */
+      GLubyte *map = (GLubyte *) strb->data;
+      if (strb->data) {
+         map += strb->stride * y;
+         map += util_format_get_blocksize(strb->format) * x;
+         *mapOut = map;
+         *rowStrideOut = strb->stride;
+      }
+      else {
+         *mapOut = NULL;
+         *rowStrideOut = 0;
+      }
+      return;
+   }
+
    usage = 0x0;
    if (mode & GL_MAP_READ_BIT)
       usage |= PIPE_TRANSFER_READ;
@@ -716,6 +732,11 @@ st_UnmapRenderbuffer(struct gl_context *ctx,
    struct st_renderbuffer *strb = st_renderbuffer(rb);
    struct pipe_context *pipe = st->pipe;
 
+   if (strb->software) {
+      /* software-allocated renderbuffer (probably an accum buffer) */
+      return;
+   }
+
    pipe_transfer_unmap(pipe, strb->transfer);
    pipe->transfer_destroy(pipe, strb->transfer);
    strb->transfer = NULL;

src/mesa/state_tracker/st_context.c

@@ -26,6 +26,7 @@
  **************************************************************************/
 
 #include "main/imports.h"
+#include "main/accum.h"
 #include "main/context.h"
 #include "main/samplerobj.h"
 #include "main/shaderobj.h"
@@ -34,7 +35,6 @@
 #include "glapi/glapi.h"
 #include "st_context.h"
 #include "st_debug.h"
-#include "st_cb_accum.h"
 #include "st_cb_bitmap.h"
 #include "st_cb_blit.h"
 #include "st_cb_bufferobjects.h"
@@ -276,7 +276,8 @@ void st_init_driver_functions(struct dd_function_table *functions)
    _mesa_init_shader_object_functions(functions);
    _mesa_init_sampler_object_functions(functions);
 
-   st_init_accum_functions(functions);
+   functions->Accum = _mesa_accum;
+
    st_init_blit_functions(functions);
    st_init_bufferobject_functions(functions);
    st_init_clear_functions(functions);

src/mesa/swrast/s_clear.c

@@ -23,13 +23,13 @@
  */
 
 #include "main/glheader.h"
+#include "main/accum.h"
 #include "main/colormac.h"
 #include "main/condrender.h"
 #include "main/macros.h"
 #include "main/imports.h"
 #include "main/mtypes.h"
 
-#include "s_accum.h"
 #include "s_context.h"
 #include "s_depth.h"
 #include "s_masking.h"
@@ -225,8 +225,7 @@ _swrast_Clear(struct gl_context *ctx, GLbitfield buffers)
          _swrast_clear_depth_buffer(ctx, ctx->DrawBuffer->_DepthBuffer);
       }
       if (buffers & BUFFER_BIT_ACCUM) {
-         _swrast_clear_accum_buffer(ctx,
-                       ctx->DrawBuffer->Attachment[BUFFER_ACCUM].Renderbuffer);
+         _mesa_clear_accum_buffer(ctx);
       }
       if (buffers & BUFFER_BIT_STENCIL) {
          _swrast_clear_stencil_buffer(ctx, ctx->DrawBuffer->_StencilBuffer);