From 781fb93877ea3a6faeefcdb48d9b463da7d954a3 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Thu, 28 Aug 2003 03:04:41 +0000
Subject: [PATCH] Added OpenGL 1.4's per-texture LOD bias.

---
 src/mesa/main/extensions.c  |  1 +
 src/mesa/main/get.c         |  1 +
 src/mesa/main/mtypes.h      |  1 +
 src/mesa/main/texobj.c      |  2 ++
 src/mesa/main/texstate.c    | 20 ++++++++++++++++++++
 src/mesa/swrast/s_texture.c |  4 ++--
 6 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 9122ff5..886311e 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -290,6 +290,7 @@ _mesa_enable_1_4_extensions(GLcontext *ctx)
    ctx->Extensions.EXT_point_parameters = GL_TRUE;
    ctx->Extensions.EXT_secondary_color = GL_TRUE;
    ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
+   ctx->Extensions.EXT_texture_lod_bias = GL_TRUE;
    ctx->Extensions.SGIS_generate_mipmap = GL_TRUE;
 }
 
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 92d6a1d..29cc146 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -6428,6 +6428,7 @@ _mesa_GetString( GLenum name )
                    ctx->Extensions.EXT_point_parameters && /*aka ARB*/
                    ctx->Extensions.EXT_secondary_color &&
                    ctx->Extensions.EXT_stencil_wrap &&
+                   ctx->Extensions.EXT_texture_lod_bias &&
                    ctx->Extensions.SGIS_generate_mipmap) {
                   if (ctx->Extensions.ARB_occlusion_query &&
                       ctx->Extensions.ARB_point_sprite &&
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 90fdd3b..5497aac 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1073,6 +1073,7 @@ struct gl_texture_object {
    GLenum MagFilter;		/**< magnification filter */
    GLfloat MinLod;		/**< min lambda, OpenGL 1.2 */
    GLfloat MaxLod;		/**< max lambda, OpenGL 1.2 */
+   GLfloat LodBias;		/**< OpenGL 1.4 */
    GLint BaseLevel;		/**< min mipmap level, OpenGL 1.2 */
    GLint MaxLevel;		/**< max mipmap level, OpenGL 1.2 */
    GLfloat MaxAnisotropy;	/**< GL_EXT_texture_filter_anisotropic */
diff --git a/src/mesa/main/texobj.c b/src/mesa/main/texobj.c
index ff0a053..6edb7e6 100644
--- a/src/mesa/main/texobj.c
+++ b/src/mesa/main/texobj.c
@@ -114,6 +114,7 @@ _mesa_initialize_texture_object( struct gl_texture_object *obj,
    obj->MagFilter = GL_LINEAR;
    obj->MinLod = -1000.0;
    obj->MaxLod = 1000.0;
+   obj->LodBias = 0.0;
    obj->BaseLevel = 0;
    obj->MaxLevel = 1000;
    obj->MaxAnisotropy = 1.0;
@@ -242,6 +243,7 @@ _mesa_copy_texture_object( struct gl_texture_object *dest,
    dest->MagFilter = src->MagFilter;
    dest->MinLod = src->MinLod;
    dest->MaxLod = src->MaxLod;
+   dest->LodBias = src->LodBias;
    dest->BaseLevel = src->BaseLevel;
    dest->MaxLevel = src->MaxLevel;
    dest->MaxAnisotropy = src->MaxAnisotropy;
diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 8110772..2c1d155 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -1399,6 +1399,14 @@ _mesa_TexParameterfv( GLenum target, GLenum pname, const GLfloat *params )
             return;
          }
          break;
+      case GL_TEXTURE_LOD_BIAS:
+         /* NOTE: this is really part of OpenGL 1.4, not EXT_texture_lod_bias*/
+         if (ctx->Extensions.EXT_texture_lod_bias) {
+            texObj->LodBias = CLAMP(params[0],
+                                    -ctx->Const.MaxTextureLodBias,
+                                    ctx->Const.MaxTextureLodBias);
+         }
+         break;
 
       default:
          _mesa_error(ctx, GL_INVALID_ENUM,
@@ -1775,6 +1783,12 @@ _mesa_GetTexParameterfv( GLenum target, GLenum pname, GLfloat *params )
             return;
          }
          break;
+      case GL_TEXTURE_LOD_BIAS:
+         if (ctx->Extensions.EXT_texture_lod_bias) {
+            *params = obj->LodBias;
+            break;
+         }
+         break;
       default:
          ; /* silence warnings */
    }
@@ -1801,6 +1815,12 @@ _mesa_GetTexParameteriv( GLenum target, GLenum pname, GLint *params )
    switch (pname) {
       case GL_TEXTURE_MAG_FILTER:
          *params = (GLint) obj->MagFilter;
+      case GL_TEXTURE_LOD_BIAS:
+         if (ctx->Extensions.EXT_texture_lod_bias) {
+            *params = (GLint) obj->LodBias;
+            break;
+         }
+         break;
          return;
       case GL_TEXTURE_MIN_FILTER:
          *params = (GLint) obj->MinFilter;
diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index 172401f..b9e0814 100644
--- a/src/mesa/swrast/s_texture.c
+++ b/src/mesa/swrast/s_texture.c
@@ -4198,11 +4198,11 @@ _swrast_texture_span( GLcontext *ctx, struct sw_span *span )
 
          /* adjust texture lod (lambda) */
          if (span->arrayMask & SPAN_LAMBDA) {
-            if (texUnit->LodBias != 0.0F) {
+            if (texUnit->LodBias + curObj->LodBias != 0.0F) {
                /* apply LOD bias, but don't clamp yet */
                GLuint i;
                for (i = 0; i < span->end; i++) {
-                  lambda[i] += texUnit->LodBias;
+                  lambda[i] += (texUnit->LodBias + curObj->LodBias);
                }
             }
 
-- 
2.7.4