improved error checking in error_check_format_type()

src/mesa/main/drawpix.c

@@ -43,6 +43,7 @@ error_check_format_type(GLcontext *ctx, GLenum format, GLenum type,
                         GLboolean drawing)
 {
    const char *readDraw = drawing ? "Draw" : "Read";
+   struct gl_framebuffer *fb = drawing ? ctx->DrawBuffer : ctx->ReadBuffer;
 
    if (ctx->Extensions.EXT_packed_depth_stencil
        && type == GL_UNSIGNED_INT_24_8_EXT
@@ -86,14 +87,14 @@ error_check_format_type(GLcontext *ctx, GLenum format, GLenum type,
       }
       break;
    case GL_STENCIL_INDEX:
-      if (ctx->DrawBuffer->Visual.stencilBits == 0) {
+      if (fb->Visual.stencilBits == 0) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "gl%sPixels(no stencil buffer)", readDraw);
          return GL_TRUE;
       }
       break;
    case GL_DEPTH_COMPONENT:
-      if (ctx->DrawBuffer->Visual.depthBits == 0) {
+      if (fb->Visual.depthBits == 0) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "gl%sPixels(no depth buffer)", readDraw);
          return GL_TRUE;
@@ -105,14 +106,13 @@ error_check_format_type(GLcontext *ctx, GLenum format, GLenum type,
          _mesa_error(ctx, GL_INVALID_ENUM, "gl%sPixels(type)", readDraw);
          return GL_TRUE;
       }
-      if (ctx->DrawBuffer->Visual.depthBits == 0 ||
-          ctx->ReadBuffer->Visual.depthBits == 0 ||
-          ctx->DrawBuffer->Visual.stencilBits == 0 ||
-          ctx->ReadBuffer->Visual.stencilBits == 0) {
+      if (fb->Visual.depthBits == 0 || fb->Visual.stencilBits == 0) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "gl%sPixels(no depth or stencil buffer)", readDraw);
          return GL_TRUE;
       }
+      ASSERT(fb->Attachment[BUFFER_DEPTH].Renderbuffer);
+      ASSERT(fb->Attachment[BUFFER_STENCIL].Renderbuffer);
       break;
    default:
       /* this should have been caught in _mesa_is_legal_format_type() */