[PATCH 1/5] wined3d: Use clamp() instead of max() for calculating the clamped cosine in the ffp lighting calculations.

[Henri Verbeet]

On typical hardware, the clamp() would be an instruction modifier, while the
max() would need an extra instruction.
---
 dlls/wined3d/glsl_shader.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/dlls/wined3d/glsl_shader.c b/dlls/wined3d/glsl_shader.c
index 740e100..280ec20 100644
--- 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);
-- 
1.8.1.5