mutter/gles/cogl-fixed-vertex-shader.glsl
Neil Roberts 38c9d46a0e * clutter/cogl/gles/cogl-gles2-wrapper.c
(cogl_gles2_wrapper_init): Get uniforms for fog parameters and
    	initialise them.
    	(cogl_wrap_glDrawArrays): Store the modelview matrix in a uniform
    	as well so that it can be used for fogging calculations.
    	(cogl_wrap_glEnable, cogl_wrap_glDisable): Enable/disable fogging.
    	(cogl_wrap_glFogx, cogl_wrap_glFogxv): Fill in wrapper to set
    	fogging parameters.

    	* clutter/cogl/gles/cogl-fixed-vertex-shader.glsl: Calculate the
    	fog amount if fogging is enabled.

    	* clutter/cogl/gles/cogl-fixed-fragment-shader.glsl: Mix with fog
    	color.

    	* clutter/cogl/gles/cogl-gles2-wrapper.h (CoglGles2Wrapper): Add
    	uniforms for fogging.
2008-05-28 17:14:17 +00:00

61 lines
1.8 KiB
GLSL

/* Per vertex attributes */
attribute vec4 vertex_attrib;
attribute vec4 tex_coord_attrib;
attribute vec4 color_attrib;
/* Transformation matrices */
uniform mat4 modelview_matrix;
uniform mat4 mvp_matrix; /* combined modelview and projection matrix */
uniform mat4 texture_matrix;
/* Outputs to the fragment shader */
varying vec4 frag_color;
varying vec2 tex_coord;
varying float fog_amount;
/* Fogging options */
uniform bool fog_enabled;
uniform int fog_mode;
uniform float fog_density;
uniform float fog_start;
uniform float fog_end;
/* Fogging modes */
const int GL_LINEAR = 0x2601;
const int GL_EXP = 0x0800;
const int GL_EXP2 = 0x0801;
void
main (void)
{
/* Calculate the transformed position */
gl_Position = mvp_matrix * vertex_attrib;
/* Calculate the transformed texture coordinate */
vec4 transformed_tex_coord = texture_matrix * tex_coord_attrib;
tex_coord = transformed_tex_coord.st / transformed_tex_coord.q;
/* Pass the interpolated vertex color on to the fragment shader */
frag_color = color_attrib;
if (fog_enabled)
{
/* Estimate the distance from the eye using just the
z-coordinate to use as the fog coord */
vec4 eye_coord = modelview_matrix * vertex_attrib;
float fog_coord = abs (eye_coord.z / eye_coord.w);
/* Calculate the fog amount per-vertex and interpolate it for
the fragment shader */
if (fog_mode == GL_EXP)
fog_amount = exp (-fog_density * fog_coord);
else if (fog_mode == GL_EXP2)
fog_amount = exp (-fog_density * fog_coord
* fog_density * fog_coord);
else
fog_amount = (fog_end - fog_coord) / (fog_end - fog_start);
fog_amount = clamp (fog_amount, 0.0, 1.0);
}
}