/*
 * The existing isotropic vertex texture functions are added to the
 * built-in functions for fragment shaders.
 */
vec4 texture1DLod    (sampler1D sampler, float coord, float lod);
vec4 texture1DProjLod(sampler1D sampler, vec2  coord, float lod);
vec4 texture1DProjLod(sampler1D sampler, vec4  coord, float lod);
vec4 texture2DLod    (sampler2D sampler, vec2 coord, float lod);
vec4 texture2DProjLod(sampler2D sampler, vec3 coord, float lod);
vec4 texture2DProjLod(sampler2D sampler, vec4 coord, float lod);
vec4 texture3DLod    (sampler3D sampler, vec3 coord, float lod);
vec4 texture3DProjLod(sampler3D sampler, vec4 coord, float lod);
vec4 textureCubeLod  (samplerCube sampler, vec3 coord, float lod);
vec4 shadow1DLod    (sampler1DShadow sampler, vec3 coord, float lod);
vec4 shadow2DLod    (sampler2DShadow sampler, vec3 coord, float lod);
vec4 shadow1DProjLod(sampler1DShadow sampler, vec4 coord, float lod);
vec4 shadow2DProjLod(sampler2DShadow sampler, vec4 coord, float lod);

/* New anisotropic texture functions, providing explicit derivatives: */
vec4 texture1DGradARB        (sampler1D sampler,
                              float P, float dPdx, float dPdy);
vec4 texture1DProjGradARB    (sampler1D sampler,
                              vec2  P, float dPdx, float dPdy);
vec4 texture1DProjGradARB    (sampler1D sampler,
                              vec4  P, float dPdx, float dPdy);

vec4 texture2DGradARB        (sampler2D sampler,
                              vec2  P, vec2  dPdx, vec2  dPdy);
vec4 texture2DProjGradARB    (sampler2D sampler,
                              vec3  P, vec2  dPdx, vec2  dPdy);
vec4 texture2DProjGradARB    (sampler2D sampler,
                              vec4  P, vec2  dPdx, vec2  dPdy);

vec4 texture3DGradARB        (sampler3D sampler,
                              vec3  P, vec3  dPdx, vec3  dPdy);
vec4 texture3DProjGradARB    (sampler3D sampler,
                              vec4  P, vec3  dPdx, vec3  dPdy);

vec4 textureCubeGradARB      (samplerCube sampler,
                              vec3  P, vec3  dPdx, vec3  dPdy);

vec4 shadow1DGradARB         (sampler1DShadow sampler,
                              vec3  P, float dPdx, float dPdy);
vec4 shadow1DProjGradARB     (sampler1DShadow sampler,
                              vec4  P, float dPdx, float dPdy);

vec4 shadow2DGradARB         (sampler2DShadow sampler,
                              vec3  P, vec2  dPdx, vec2  dPdy);
vec4 shadow2DProjGradARB     (sampler2DShadow sampler,
                              vec4  P, vec2  dPdx, vec2  dPdy);

#ifdef GL_ARB_texture_rectangle
vec4 texture2DRectGradARB    (sampler2DRect sampler,
                              vec2  P, vec2  dPdx, vec2  dPdy);
vec4 texture2DRectProjGradARB(sampler2DRect sampler,
                              vec3  P, vec2  dPdx, vec2  dPdy);
vec4 texture2DRectProjGradARB(sampler2DRect sampler,
                              vec4  P, vec2  dPdx, vec2  dPdy);

vec4 shadow2DRectGradARB     (sampler2DRectShadow sampler,
                              vec3  P, vec2  dPdx, vec2  dPdy);
vec4 shadow2DRectProjGradARB (sampler2DRectShadow sampler,
                              vec4  P, vec2  dPdx, vec2  dPdy);
#endif