wined3d: Use clamp() instead of max() for calculating the clamped cosine in the…

wined3d: Use clamp() instead of max() for calculating the clamped cosine in the ffp lighting calculations. On typical hardware, the clamp() would be an instruction modifier, while the max() would need an extra instruction.

wined3d: Use clamp() instead of max() for calculating the clamped cosine in the…
ff6ce4c6 · Henri Verbeet · Alexandre Julliard · 725b069e · ff6ce4c6
Commit ff6ce4c6 authored Sep 04, 2013 by Henri Verbeet Committed by Alexandre Julliard Sep 04, 2013
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Showing with 4 additions and 3 deletions

glsl_shader.c dlls/wined3d/glsl_shader.c +4 -3

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--- a/dlls/wined3d/glsl_shader.c
+++ b/dlls/wined3d/glsl_shader.c
@@ -4940,7 +4940,7 @@ static void shader_glsl_ffp_vertex_lighting(struct wined3d_shader_buffer *buffer
                if (!settings->normal)
                    break;
                shader_addline(buffer, "dir = normalize(dir);\n");
-                shader_addline(buffer, "diffuse += (max(0.0, dot(dir, normal))"
+                shader_addline(buffer, "diffuse += (clamp(dot(dir, normal), 0.0, 1.0)"
                        " * gl_LightSource[%u].diffuse.xyz) / att;\n", i);
                if (settings->localviewer)
                    shader_addline(buffer, "t = dot(normal, normalize(dir - normalize(ec_pos.xyz)));\n");
@@ -4965,7 +4965,7 @@ static void shader_glsl_ffp_vertex_lighting(struct wined3d_shader_buffer *buffer
                shader_addline(buffer, "ambient += gl_LightSource[%u].ambient.xyz * att;\n", i);
                if (!settings->normal)
                    break;
-                shader_addline(buffer, "diffuse += (max(0.0, dot(dir, normal))"
+                shader_addline(buffer, "diffuse += (clamp(dot(dir, normal), 0.0, 1.0)"
                        " * gl_LightSource[%u].diffuse.xyz) * att;\n", i);
                if (settings->localviewer)
                    shader_addline(buffer, "t = dot(normal, normalize(dir - normalize(ec_pos.xyz)));\n");
@@ -4980,7 +4980,8 @@ static void shader_glsl_ffp_vertex_lighting(struct wined3d_shader_buffer *buffer
                if (!settings->normal)
                    break;
                shader_addline(buffer, "dir = normalize(gl_LightSource[%u].position.xyz);\n", i);
-                shader_addline(buffer, "diffuse += max(0.0, dot(dir, normal)) * gl_LightSource[%u].diffuse.xyz;\n", i);
+                shader_addline(buffer, "diffuse += clamp(dot(dir, normal), 0.0, 1.0)"
+                        " * gl_LightSource[%u].diffuse.xyz;\n", i);
                shader_addline(buffer, "t = dot(normal, gl_LightSource[%u].halfVector.xyz);\n", i);
                shader_addline(buffer, "if (t > 0.0) specular += pow(t, gl_FrontMaterial.shininess)"
                        " * gl_LightSource[%u].specular;\n", i);