driconf: add force_glsl_abs_sqrt option

This will allow to force computing the absolute value for sqrt()
and inversesqrt() in order to follow D3D9 behaviour for buggy
apps that rely on it.

Signed-off-by: Samuel Pitoiset <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

5 files changed, 17 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/common/xmlpool/t_options.h b/src/mesa/drivers/dri/common/xmlpool/t_options.h
index c7c658d0aac..cd4f0252b92 100644
--- a/src/mesa/drivers/dri/common/xmlpool/t_options.h
+++ b/src/mesa/drivers/dri/common/xmlpool/t_options.h
@@ -120,6 +120,11 @@ DRI_CONF_OPT_BEGIN_B(allow_higher_compat_version, def) \
         DRI_CONF_DESC(en,gettext("Allow a higher compat profile (version 3.1+) for apps that request it")) \
 DRI_CONF_OPT_END
 
+#define DRI_CONF_FORCE_GLSL_ABS_SQRT(def) \
+DRI_CONF_OPT_BEGIN_B(force_glsl_abs_sqrt, def) \
+        DRI_CONF_DESC(en,gettext("Force computing the absolute value for sqrt() and inversesqrt()")) \
+DRI_CONF_OPT_END
+
 
 
 /**
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 648ae508145..624abe6d523 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -937,6 +937,9 @@ brw_process_driconf_options(struct brw_context *brw)
    ctx->Const.AllowHigherCompatVersion =
       driQueryOptionb(options, "allow_higher_compat_version");
 
+   ctx->Const.ForceGLSLAbsSqrt =
+      driQueryOptionb(options, "force_glsl_abs_sqrt");
+
    ctx->Const.GLSLZeroInit = driQueryOptionb(options, "glsl_zero_init");
 
    brw->dual_color_blend_by_location =
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index a35cf69eede..c7f111d04af 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -90,6 +90,7 @@ DRI_CONF_BEGIN
       DRI_CONF_DUAL_COLOR_BLEND_BY_LOCATION("false")
       DRI_CONF_ALLOW_GLSL_EXTENSION_DIRECTIVE_MIDSHADER("false")
       DRI_CONF_ALLOW_HIGHER_COMPAT_VERSION("false")
+      DRI_CONF_FORCE_GLSL_ABS_SQRT("false")
 
       DRI_CONF_OPT_BEGIN_B(shader_precompile, "true")
 	 DRI_CONF_DESC(en, "Perform code generation at shader link time.")
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 7e970843d5c..be78b96810d 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3556,6 +3556,12 @@ struct gl_constants
    GLboolean AllowHigherCompatVersion;
 
    /**
+    * Force computing the absolute value for sqrt() and inversesqrt() to follow
+    * D3D9 when apps rely on this behaviour.
+    */
+   GLboolean ForceGLSLAbsSqrt;
+
+   /**
     * Force uninitialized variables to default to zero.
     */
    GLboolean GLSLZeroInit;
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 0dc2580a88c..16f86856a34 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -881,6 +881,8 @@ void st_init_extensions(struct pipe_screen *screen,
 
    consts->AllowHigherCompatVersion = options->allow_higher_compat_version;
 
+   consts->ForceGLSLAbsSqrt = options->force_glsl_abs_sqrt;
+
    consts->dri_config_options_sha1 = options->config_options_sha1;
 
    if (consts->GLSLVersion >= 400)