Mesa: Add support for GL_OES_texture_*float* extensions.

This patch series adds support for following GLES2 Texture Float extensions:
1)GL_OES_texture_float,
2)GL_OES_texture_half_float,
3)GL_OES_texture_float_linear,
4)GL_OES_texture_half_float_linear.

This patch adds basic infrastructure and needed boolean flags to advertise
support for these extensions, by default the support is disabled. Next patch
in the series introduces support for HALF_FLOAT_OES token.

v4: take assert away and make valid_filter_for_float conditional (Tapani),
    fix the alphabetical order (Emil)

Signed-off-by: Kevin Rogovin <kevin.rogovin@intel.com>
Signed-off-by: Kalyan Kondapally <kalyan.kondapally@intel.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>

4 files changed, 132 insertions, 0 deletions

diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 16f1241..bfe7d99 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -317,6 +317,10 @@ static const struct extension extension_table[] = {
    { "GL_OES_texture_3D",                          o(EXT_texture3D),                                      ES2, 2005 },
    { "GL_OES_texture_cube_map",                    o(ARB_texture_cube_map),                         ES1,       2007 },
    { "GL_OES_texture_env_crossbar",                o(ARB_texture_env_crossbar),                     ES1,       2005 },
+   { "GL_OES_texture_float",                       o(OES_texture_float),                                  ES2, 2005 },
+   { "GL_OES_texture_float_linear",                o(OES_texture_float_linear),                           ES2, 2005 },
+   { "GL_OES_texture_half_float",                  o(OES_texture_half_float),                             ES2, 2005 },
+   { "GL_OES_texture_half_float_linear",           o(OES_texture_half_float_linear),                      ES2, 2005 },
    { "GL_OES_texture_mirrored_repeat",             o(dummy_true),                                   ES1,       2005 },
    { "GL_OES_texture_npot",                        o(ARB_texture_non_power_of_two),                 ES1 | ES2, 2005 },
    { "GL_OES_vertex_array_object",                 o(dummy_true),                                   ES1 | ES2, 2010 },
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 145927a..81a7c0e 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1220,6 +1220,8 @@ struct gl_texture_object
    GLboolean Purgeable;        /**< Is the buffer purgeable under memory
                                     pressure? */
    GLboolean Immutable;        /**< GL_ARB_texture_storage */
+   GLboolean _IsFloat;         /**< GL_OES_float_texture */
+   GLboolean _IsHalfFloat;     /**< GL_OES_half_float_texture */
 
    GLuint MinLevel;            /**< GL_ARB_texture_view */
    GLuint MinLayer;            /**< GL_ARB_texture_view */
@@ -3859,6 +3861,10 @@ struct gl_extensions
    GLboolean OES_draw_texture;
    GLboolean OES_depth_texture_cube_map;
    GLboolean OES_EGL_image_external;
+   GLboolean OES_texture_float;
+   GLboolean OES_texture_float_linear;
+   GLboolean OES_texture_half_float;
+   GLboolean OES_texture_half_float_linear;
    GLboolean OES_compressed_ETC1_RGB8_texture;
    GLboolean extension_sentinel;
    /** The extension string */
diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index 5ada94f..ed08ddb 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -62,7 +62,58 @@
  */
 #define NEW_COPY_TEX_STATE (_NEW_BUFFERS | _NEW_PIXEL)
 
+/**
+ * Returns a corresponding internal floating point format for a given base
+ * format as specifed by OES_texture_float. In case of GL_FLOAT, the internal
+ * format needs to be a 32 bit component and in case of GL_HALF_FLOAT_OES it
+ * needs to be a 16 bit component.
+ *
+ * For example, given base format GL_RGBA, type GL_Float return GL_RGBA32F_ARB.
+ */
+static GLenum
+adjust_for_oes_float_texture(GLenum format, GLenum type)
+{
+   switch (type) {
+   case GL_FLOAT:
+      switch (format) {
+      case GL_RGBA:
+         return GL_RGBA32F;
+      case GL_RGB:
+         return GL_RGB32F;
+      case GL_ALPHA:
+         return GL_ALPHA32F_ARB;
+      case GL_LUMINANCE:
+         return GL_LUMINANCE32F_ARB;
+      case GL_LUMINANCE_ALPHA:
+         return GL_LUMINANCE_ALPHA32F_ARB;
+      default:
+         break;
+      }
+      break;
 
+   case GL_HALF_FLOAT_OES:
+      switch (format) {
+      case GL_RGBA:
+         return GL_RGBA16F;
+      case GL_RGB:
+         return GL_RGB16F;
+      case GL_ALPHA:
+         return GL_ALPHA16F_ARB;
+      case GL_LUMINANCE:
+         return GL_LUMINANCE16F_ARB;
+      case GL_LUMINANCE_ALPHA:
+         return GL_LUMINANCE_ALPHA16F_ARB;
+      default:
+         break;
+      }
+      break;
+
+   default:
+      break;
+   }
+
+   return format;
+}
 
 /**
  * Return the simple base format for a given internal texture format.
@@ -3182,6 +3233,19 @@ teximage(struct gl_context *ctx, GLboolean compressed, GLuint dims,
       texFormat = _mesa_glenum_to_compressed_format(internalFormat);
    }
    else {
+      /* In case of HALF_FLOAT_OES or FLOAT_OES, find corresponding sized
+       * internal floating point format for the given base format.
+       */
+      if (_mesa_is_gles(ctx) && format == internalFormat) {
+         if (type == GL_FLOAT) {
+            texObj->_IsFloat = GL_TRUE;
+         } else if (type == GL_HALF_FLOAT_OES || type == GL_HALF_FLOAT) {
+            texObj->_IsHalfFloat = GL_TRUE;
+         }
+
+         internalFormat = adjust_for_oes_float_texture(format, type);
+      }
+
       texFormat = _mesa_choose_texture_format(ctx, texObj, target, level,
                                               internalFormat, format, type);
    }
diff --git a/src/mesa/main/texobj.c b/src/mesa/main/texobj.c
index a99dd7a..59090db 100644
--- a/src/mesa/main/texobj.c
+++ b/src/mesa/main/texobj.c
@@ -49,6 +49,54 @@
 /** \name Internal functions */
 /*@{*/
 
+/**
+ * This function checks for all valid combinations of Min and Mag filters for
+ * Float types, when extensions like OES_texture_float and
+ * OES_texture_float_linear are supported. OES_texture_float mentions support
+ * for NEAREST, NEAREST_MIPMAP_NEAREST magnification and minification filters.
+ * Mag filters like LINEAR and min filters like NEAREST_MIPMAP_LINEAR,
+ * LINEAR_MIPMAP_NEAREST and LINEAR_MIPMAP_LINEAR are only valid in case
+ * OES_texture_float_linear is supported.
+ *
+ * Returns true in case the filter is valid for given Float type else false.
+ */
+static bool
+valid_filter_for_float(const struct gl_context *ctx,
+                       const struct gl_texture_object *obj)
+{
+   switch (obj->Sampler.MagFilter) {
+   case GL_LINEAR:
+      if (obj->_IsHalfFloat && !ctx->Extensions.OES_texture_half_float_linear) {
+         return false;
+      } else if (obj->_IsFloat && !ctx->Extensions.OES_texture_float_linear) {
+         return false;
+      }
+   case GL_NEAREST:
+   case GL_NEAREST_MIPMAP_NEAREST:
+      break;
+   default:
+      unreachable("Invalid mag filter");
+   }
+
+   switch (obj->Sampler.MinFilter) {
+   case GL_LINEAR:
+   case GL_NEAREST_MIPMAP_LINEAR:
+   case GL_LINEAR_MIPMAP_NEAREST:
+   case GL_LINEAR_MIPMAP_LINEAR:
+      if (obj->_IsHalfFloat && !ctx->Extensions.OES_texture_half_float_linear) {
+         return false;
+      } else if (obj->_IsFloat && !ctx->Extensions.OES_texture_float_linear) {
+         return false;
+      }
+   case GL_NEAREST:
+   case GL_NEAREST_MIPMAP_NEAREST:
+      break;
+   default:
+      unreachable("Invalid min filter");
+   }
+
+   return true;
+}
 
 /**
  * Return the gl_texture_object for a given ID.
@@ -408,6 +456,8 @@ _mesa_copy_texture_object( struct gl_texture_object *dest,
    dest->_MipmapComplete = src->_MipmapComplete;
    COPY_4V(dest->Swizzle, src->Swizzle);
    dest->_Swizzle = src->_Swizzle;
+   dest->_IsHalfFloat = src->_IsHalfFloat;
+   dest->_IsFloat = src->_IsFloat;
 
    dest->RequiredTextureImageUnits = src->RequiredTextureImageUnits;
 }
@@ -641,6 +691,14 @@ _mesa_test_texobj_completeness( const struct gl_context *ctx,
       t->_IsIntegerFormat = datatype == GL_INT || datatype == GL_UNSIGNED_INT;
    }
 
+   /* Check if the texture type is Float or HalfFloatOES and ensure Min and Mag
+    * filters are supported in this case.
+    */
+   if (_mesa_is_gles(ctx) && !valid_filter_for_float(ctx, t)) {
+      incomplete(t, BASE, "Filter is not supported with Float types.");
+      return;
+   }
+
    /* Compute _MaxLevel (the maximum mipmap level we'll sample from given the
     * mipmap image sizes and GL_TEXTURE_MAX_LEVEL state).
     */