iris: Use R/RG instead of I/L/A when sampling

diff --git a/src/gallium/drivers/iris/iris_formats.c b/src/gallium/drivers/iris/iris_formats.c
index 2c726cb5fdee7ae09ee5e143255b1df43f56266e..290b65880a180335ba9342e2b6f9b7404d3be56e 100644 (file)
--- a/src/gallium/drivers/iris/iris_formats.c
+++ b/src/gallium/drivers/iris/iris_formats.c
@@ -400,6 +400,26 @@ iris_isl_format_for_pipe_format(enum pipe_format pf)
    return table[pf];
 }
 
+static enum pipe_format
+alpha_to_red(enum pipe_format pf)
+{
+   switch (pf) {
+   case PIPE_FORMAT_A8_UNORM:  return PIPE_FORMAT_R8_UNORM;
+   case PIPE_FORMAT_A16_UNORM: return PIPE_FORMAT_R16_UNORM;
+   case PIPE_FORMAT_A8_SNORM:  return PIPE_FORMAT_R8_SNORM;
+   case PIPE_FORMAT_A16_SNORM: return PIPE_FORMAT_R16_SNORM;
+   case PIPE_FORMAT_A16_FLOAT: return PIPE_FORMAT_R16_FLOAT;
+   case PIPE_FORMAT_A32_FLOAT: return PIPE_FORMAT_R32_FLOAT;
+   case PIPE_FORMAT_A8_UINT:   return PIPE_FORMAT_A8_UINT;
+   case PIPE_FORMAT_A8_SINT:   return PIPE_FORMAT_A8_SINT;
+   case PIPE_FORMAT_A16_UINT:  return PIPE_FORMAT_R16_UINT;
+   case PIPE_FORMAT_A16_SINT:  return PIPE_FORMAT_R16_SINT;
+   case PIPE_FORMAT_A32_UINT:  return PIPE_FORMAT_R32_UINT;
+   case PIPE_FORMAT_A32_SINT:  return PIPE_FORMAT_R32_SINT;
+   default:                    return pf;
+   }
+}
+
 struct iris_format_info
 iris_format_for_usage(const struct gen_device_info *devinfo,
                       enum pipe_format pformat,
@@ -407,6 +427,17 @@ iris_format_for_usage(const struct gen_device_info *devinfo,
 {
    struct isl_swizzle swizzle = ISL_SWIZZLE_IDENTITY;
 
+   if ((usage & ISL_SURF_USAGE_TEXTURE_BIT) && !util_format_is_srgb(pformat)) {
+      if (util_format_is_intensity(pformat)) {
+         swizzle = ISL_SWIZZLE(RED, RED, RED, RED);
+      } else if (util_format_is_luminance(pformat)) {
+         swizzle = ISL_SWIZZLE(RED, RED, RED, ONE);
+      } else if (util_format_is_alpha(pformat)) {
+         pformat = alpha_to_red(pformat);
+         swizzle = ISL_SWIZZLE(ZERO, ZERO, ZERO, RED);
+      }
+   }
+
    enum isl_format format = iris_isl_format_for_pipe_format(pformat);
 
    /* Convert RGBX into RGBA for rendering or typed image access. */