st/mesa: avoid large stack allocations in readpixels code

diff --git a/src/mesa/state_tracker/st_cb_readpixels.c b/src/mesa/state_tracker/st_cb_readpixels.c
index 620da07..0507be7 100644 (file)
--- a/src/mesa/state_tracker/st_cb_readpixels.c
+++ b/src/mesa/state_tracker/st_cb_readpixels.c
@@ -328,7 +328,7 @@ st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei h
 {
    struct st_context *st = st_context(ctx);
    struct pipe_context *pipe = st->pipe;
-   GLfloat temp[MAX_WIDTH][4];
+   GLfloat (*temp)[4];
    const GLbitfield transferOps = ctx->_ImageTransferState;
    GLsizei i, j;
    GLint yStep, dfStride;
@@ -381,6 +381,13 @@ st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei h
       return;
    }
 
+   /* allocate temp pixel row buffer */
+   temp = (GLfloat (*)[4]) malloc(4 * width * sizeof(GLfloat));
+   if (!temp) {
+      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
+      return;
+   }
+
    if (format == GL_RGBA && type == GL_FLOAT) {
       /* write tile(row) directly into user's buffer */
       df = (GLfloat *) _mesa_image_address2d(&clippedPacking, dest, width,
@@ -533,6 +540,8 @@ st_readpixels(struct gl_context *ctx, GLint x, GLint y, GLsizei width, GLsizei h
       }
    }
 
+   free(temp);
+
    pipe->transfer_destroy(pipe, trans);
 
    _mesa_unmap_pbo_dest(ctx, &clippedPacking);