[Mesa-dev] [PATCH] mesa: add NV_read_{depth, stencil, depth_stencil} extensions

[Rob Clark]

From: Rob Clark <robclark at freedesktop.org>

These extensions allow reading depth/stencil for GLES contexts, which is
useful for tools like apitrace.

Signed-off-by: Rob Clark <robclark at freedesktop.org>
---
v2: rework format/type checking

 src/mesa/main/extensions.c |  3 +++
 src/mesa/main/readpix.c    | 48 +++++++++++++++++++++++++++++++++++++---------
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 2dbfabd..d934d19 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -385,6 +385,9 @@ static const struct extension extension_table[] = {
    { "GL_NV_point_sprite",                         o(NV_point_sprite),                         GL,             2001 },
    { "GL_NV_primitive_restart",                    o(NV_primitive_restart),                    GLL,            2002 },
    { "GL_NV_read_buffer",                          o(dummy_true),                              ES2,            2011 },
+   { "GL_NV_read_depth",                           o(dummy_true),                              ES2,            2011 },
+   { "GL_NV_read_depth_stencil",                   o(dummy_true),                              ES2,            2011 },
+   { "GL_NV_read_stencil",                         o(dummy_true),                              ES2,            2011 },
    { "GL_NV_texgen_reflection",                    o(dummy_true),                              GLL,            1999 },
    { "GL_NV_texture_barrier",                      o(NV_texture_barrier),                      GL,             2009 },
    { "GL_NV_texture_env_combine4",                 o(NV_texture_env_combine4),                 GLL,            1999 },
diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
index 2744232..d826ecf 100644
--- a/src/mesa/main/readpix.c
+++ b/src/mesa/main/readpix.c
@@ -916,10 +916,8 @@ read_pixels_es3_error_check(GLenum format, GLenum type,
    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
    GLboolean is_unsigned_int = GL_FALSE;
    GLboolean is_signed_int = GL_FALSE;
-
-   if (!_mesa_is_color_format(internalFormat)) {
-      return GL_INVALID_OPERATION;
-   }
+   GLboolean is_float_depth = (internalFormat == GL_DEPTH_COMPONENT32F) ||
+         (internalFormat == GL_DEPTH32F_STENCIL8);
 
    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
    if (!is_unsigned_int) {
@@ -950,6 +948,43 @@ read_pixels_es3_error_check(GLenum format, GLenum type,
           (is_unsigned_int && type == GL_UNSIGNED_INT))
          return GL_NO_ERROR;
       break;
+   case GL_DEPTH_STENCIL:
+      switch (type) {
+      case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
+         if (is_float_depth)
+            return GL_NO_ERROR;
+         break;
+      case GL_UNSIGNED_INT_24_8:
+         if (!is_float_depth)
+            return GL_NO_ERROR;
+         break;
+      default:
+         return GL_INVALID_ENUM;
+      }
+      break;
+   case GL_DEPTH_COMPONENT:
+      switch (type) {
+      case GL_FLOAT:
+         if (is_float_depth)
+            return GL_NO_ERROR;
+         break;
+      case GL_UNSIGNED_SHORT:
+      case GL_UNSIGNED_INT_24_8:
+         if (!is_float_depth)
+            return GL_NO_ERROR;
+         break;
+      default:
+         return GL_INVALID_ENUM;
+      }
+      break;
+   case GL_STENCIL_INDEX:
+      switch (type) {
+      case GL_UNSIGNED_BYTE:
+         return GL_NO_ERROR;
+      default:
+         return GL_INVALID_ENUM;
+      }
+      break;
    }
 
    return GL_INVALID_OPERATION;
@@ -1023,11 +1058,6 @@ _mesa_ReadnPixelsARB( GLint x, GLint y, GLsizei width, GLsizei height,
          err = read_pixels_es3_error_check(format, type, rb);
       }
 
-      if (err == GL_NO_ERROR && (format == GL_DEPTH_COMPONENT
-          || format == GL_DEPTH_STENCIL)) {
-         err = GL_INVALID_ENUM;
-      }
-
       if (err != GL_NO_ERROR) {
          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
                      _mesa_enum_to_string(format),
-- 
2.4.3