From 78636289b073d67209a20145ef0dc003f2d77db6 Mon Sep 17 00:00:00 2001

From: Sian Cao <yinshuiboy@gmail.com>

Date: Tue, 12 Apr 2016 11:36:51 +0800

Subject: Add GL_ARB_shader_texture_lod support

The patch is used to do lod biased texturing. I can achieve

faster blurring of images instead of using large blur radius.

Signed-off-by:

 Sian Cao <yinshuiboy@gmail.com>: initial

---

 cogl/cogl-context.h                |  1 +

 cogl/cogl-glsl-shader.c            | 13 +++++++++++--

 cogl/cogl-types.h                  |  3 ++-

 cogl/driver/gl/gl/cogl-driver-gl.c |  7 +++++++

 4 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/cogl/cogl-context.h b/cogl/cogl-context.h

index 07badeb..261ce49 100644

--- a/cogl/cogl-context.h

+++ b/cogl/cogl-context.h

@@ -290,6 +290,7 @@ typedef enum _CoglFeatureID

   COGL_FEATURE_ID_PER_VERTEX_POINT_SIZE,

   COGL_FEATURE_ID_TEXTURE_RG,

   COGL_FEATURE_ID_BUFFER_AGE,

+  COGL_FEATURE_ID_SHADER_TEXTURE_LOD,

   /*< private >*/

   _COGL_N_FEATURE_IDS   /*< skip >*/

diff --git a/cogl/cogl-glsl-shader.c b/cogl/cogl-glsl-shader.c

index 196e0c7..4fb0eb5 100644

--- a/cogl/cogl-glsl-shader.c

+++ b/cogl/cogl-glsl-shader.c

@@ -87,8 +87,8 @@ _cogl_glsl_shader_set_source_with_boilerplate (CoglContext *ctx,

   const char *vertex_boilerplate;

   const char *fragment_boilerplate;

-  const char **strings = g_alloca (sizeof (char *) * (count_in + 4));

-  GLint *lengths = g_alloca (sizeof (GLint) * (count_in + 4));

+  const char **strings = g_alloca (sizeof (char *) * (count_in + 5));

+  GLint *lengths = g_alloca (sizeof (GLint) * (count_in + 5));

   char *version_string;

   int count = 0;

@@ -111,6 +111,15 @@ _cogl_glsl_shader_set_source_with_boilerplate (CoglContext *ctx,

       lengths[count++] = sizeof (texture_3d_extension) - 1;

     }

+  if (_cogl_has_private_feature (ctx, COGL_PRIVATE_FEATURE_GL_PROGRAMMABLE) &&

+      cogl_has_feature (ctx, COGL_FEATURE_ID_SHADER_TEXTURE_LOD))

+    {

+      static const char shader_texture_lod_ext[] =

+        "#extension GL_ARB_shader_texture_lod : enable\n";

+      strings[count] = shader_texture_lod_ext;

+      lengths[count++] = sizeof (shader_texture_lod_ext) - 1;

+    }

+

   if (shader_gl_type == GL_VERTEX_SHADER)

     {

       strings[count] = vertex_boilerplate;

diff --git a/cogl/cogl-types.h b/cogl/cogl-types.h

index 6accf8d..77964c6 100644

--- a/cogl/cogl-types.h

+++ b/cogl/cogl-types.h

@@ -470,7 +470,8 @@ typedef enum

   COGL_FEATURE_MAP_BUFFER_FOR_READ    = (1 << 21),

   COGL_FEATURE_MAP_BUFFER_FOR_WRITE   = (1 << 22),

   COGL_FEATURE_ONSCREEN_MULTIPLE      = (1 << 23),

-  COGL_FEATURE_DEPTH_TEXTURE          = (1 << 24)

+  COGL_FEATURE_DEPTH_TEXTURE          = (1 << 24),

+  COGL_FEATURE_SHADER_TEXTURE_LOD     = (1 << 25)

 } CoglFeatureFlags;

 /**

diff --git a/cogl/driver/gl/gl/cogl-driver-gl.c b/cogl/driver/gl/gl/cogl-driver-gl.c

index 716d1dd..f305b6a 100644

--- a/cogl/driver/gl/gl/cogl-driver-gl.c

+++ b/cogl/driver/gl/gl/cogl-driver-gl.c

@@ -568,6 +568,13 @@ _cogl_driver_update_features (CoglContext *ctx,

                       COGL_FEATURE_ID_TEXTURE_RECTANGLE, TRUE);

     }

+  if (_cogl_check_extension ("GL_ARB_shader_texture_lod", gl_extensions))

+    {

+      flags |= COGL_FEATURE_SHADER_TEXTURE_LOD;

+      COGL_FLAGS_SET (ctx->features,

+                      COGL_FEATURE_ID_SHADER_TEXTURE_LOD, TRUE);

+    }

+

   if (ctx->glTexImage3D)

     {

       flags |= COGL_FEATURE_TEXTURE_3D;

-- 

2.9.5