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authorBrian Paul <[email protected]>2008-08-19 14:34:59 -0600
committerBrian Paul <[email protected]>2008-08-19 14:35:32 -0600
commit84a496746e1b01f4b11c4a44dd698b904ec83572 (patch)
treea48e24fb9be06c02e928e08f7f12d9fd20c728aa /src
parente90c0c976d89d108a8220b538e02be173cf308fe (diff)
gallium: implement a fast-path for glReadPixels for common cases
Diffstat (limited to 'src')
-rw-r--r--src/mesa/state_tracker/st_cb_readpixels.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/src/mesa/state_tracker/st_cb_readpixels.c b/src/mesa/state_tracker/st_cb_readpixels.c
index eb71779cc9f..39f5856f94e 100644
--- a/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/src/mesa/state_tracker/st_cb_readpixels.c
@@ -163,6 +163,124 @@ st_get_color_read_renderbuffer(GLcontext *ctx)
/**
+ * Try to do glReadPixels in a fast manner for common cases.
+ * \return GL_TRUE for success, GL_FALSE for failure
+ */
+static GLboolean
+st_fast_readpixels(GLcontext *ctx, struct st_renderbuffer *strb,
+ GLint x, GLint y, GLsizei width, GLsizei height,
+ GLenum format, GLenum type,
+ const struct gl_pixelstore_attrib *pack,
+ GLvoid *dest)
+{
+ enum combination {
+ A8R8G8B8_UNORM_TO_RGBA_UBYTE,
+ A8R8G8B8_UNORM_TO_RGB_UBYTE,
+ A8R8G8B8_UNORM_TO_BGRA_UINT
+ } combo;
+
+ if (ctx->_ImageTransferState)
+ return GL_FALSE;
+
+ if (strb->format == PIPE_FORMAT_A8R8G8B8_UNORM &&
+ format == GL_RGBA && type == GL_UNSIGNED_BYTE) {
+ combo = A8R8G8B8_UNORM_TO_RGBA_UBYTE;
+ }
+ else if (strb->format == PIPE_FORMAT_A8R8G8B8_UNORM &&
+ format == GL_RGB && type == GL_UNSIGNED_BYTE) {
+ combo = A8R8G8B8_UNORM_TO_RGB_UBYTE;
+ }
+ else if (strb->format == PIPE_FORMAT_A8R8G8B8_UNORM &&
+ format == GL_BGRA && type == GL_UNSIGNED_INT_8_8_8_8_REV) {
+ combo = A8R8G8B8_UNORM_TO_BGRA_UINT;
+ }
+ else {
+ return GL_FALSE;
+ }
+
+ /*printf("st_fast_readpixels combo %d\n", (GLint) combo);*/
+
+ {
+ struct pipe_context *pipe = ctx->st->pipe;
+ struct pipe_screen *screen = pipe->screen;
+ struct pipe_surface *surf;
+ const GLubyte *map;
+ GLubyte *dst;
+ GLint row, col, dy, dstStride;
+
+ surf = screen->get_tex_surface(screen, strb->texture, 0, 0, 0,
+ PIPE_BUFFER_USAGE_CPU_READ);
+ if (!surf) {
+ return GL_FALSE;
+ }
+
+ map = screen->surface_map(screen, surf, PIPE_BUFFER_USAGE_CPU_READ);
+ if (!map) {
+ pipe_surface_reference(&surf, NULL);
+ return GL_FALSE;
+ }
+
+ if (st_fb_orientation(ctx->ReadBuffer) == Y_0_TOP) {
+ y = surf->height - y - 1;
+ dy = -1;
+ }
+ else {
+ dy = 1;
+ }
+
+ dst = _mesa_image_address2d(pack, dest, width, height,
+ format, type, 0, 0);
+ dstStride = _mesa_image_row_stride(pack, width, format, type);
+
+ switch (combo) {
+ case A8R8G8B8_UNORM_TO_RGBA_UBYTE:
+ for (row = 0; row < height; row++) {
+ const GLubyte *src = map + y * surf->stride + x * 4;
+ for (col = 0; col < width; col++) {
+ GLuint pixel = ((GLuint *) src)[col];
+ dst[col*4+0] = (pixel >> 16) & 0xff;
+ dst[col*4+1] = (pixel >> 8) & 0xff;
+ dst[col*4+2] = (pixel >> 0) & 0xff;
+ dst[col*4+3] = (pixel >> 24) & 0xff;
+ }
+ dst += dstStride;
+ y += dy;
+ }
+ break;
+ case A8R8G8B8_UNORM_TO_RGB_UBYTE:
+ for (row = 0; row < height; row++) {
+ const GLubyte *src = map + y * surf->stride + x * 4;
+ for (col = 0; col < width; col++) {
+ GLuint pixel = ((GLuint *) src)[col];
+ dst[col*3+0] = (pixel >> 16) & 0xff;
+ dst[col*3+1] = (pixel >> 8) & 0xff;
+ dst[col*3+2] = (pixel >> 0) & 0xff;
+ }
+ dst += dstStride;
+ y += dy;
+ }
+ break;
+ case A8R8G8B8_UNORM_TO_BGRA_UINT:
+ for (row = 0; row < height; row++) {
+ const GLubyte *src = map + y * surf->stride + x * 4;
+ memcpy(dst, src, 4 * width);
+ dst += dstStride;
+ y += dy;
+ }
+ break;
+ default:
+ ; /* nothing */
+ }
+
+ screen->surface_unmap(screen, surf);
+ pipe_surface_reference(&surf, NULL);
+ }
+
+ return GL_TRUE;
+}
+
+
+/**
* Do glReadPixels by getting rows from the framebuffer surface with
* get_tile(). Convert to requested format/type with Mesa image routines.
* Image transfer ops are done in software too.
@@ -219,6 +337,14 @@ st_readpixels(GLcontext *ctx, GLint x, GLint y, GLsizei width, GLsizei height,
if (!strb)
return;
+ /* try a fast-path readpixels before anything else */
+ if (st_fast_readpixels(ctx, strb, x, y, width, height,
+ format, type, pack, dest)) {
+ /* success! */
+ _mesa_unmap_readpix_pbo(ctx, &clippedPacking);
+ return;
+ }
+
if (format == GL_RGBA && type == GL_FLOAT) {
/* write tile(row) directly into user's buffer */
df = (GLfloat *) _mesa_image_address2d(&clippedPacking, dest, width,