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8d7bf93909
(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.
61 lines
1.8 KiB
GLSL
61 lines
1.8 KiB
GLSL
/* Per vertex attributes */
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attribute vec4 vertex_attrib;
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attribute vec4 tex_coord_attrib;
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attribute vec4 color_attrib;
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/* Transformation matrices */
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uniform mat4 modelview_matrix;
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uniform mat4 mvp_matrix; /* combined modelview and projection matrix */
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uniform mat4 texture_matrix;
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/* Outputs to the fragment shader */
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varying vec4 frag_color;
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varying vec2 tex_coord;
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varying float fog_amount;
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/* Fogging options */
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uniform bool fog_enabled;
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uniform int fog_mode;
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uniform float fog_density;
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uniform float fog_start;
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uniform float fog_end;
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/* Fogging modes */
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const int GL_LINEAR = 0x2601;
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const int GL_EXP = 0x0800;
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const int GL_EXP2 = 0x0801;
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void
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main (void)
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{
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/* Calculate the transformed position */
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gl_Position = mvp_matrix * vertex_attrib;
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/* Calculate the transformed texture coordinate */
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vec4 transformed_tex_coord = texture_matrix * tex_coord_attrib;
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tex_coord = transformed_tex_coord.st / transformed_tex_coord.q;
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/* Pass the interpolated vertex color on to the fragment shader */
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frag_color = color_attrib;
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if (fog_enabled)
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{
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/* Estimate the distance from the eye using just the
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z-coordinate to use as the fog coord */
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vec4 eye_coord = modelview_matrix * vertex_attrib;
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float fog_coord = abs (eye_coord.z / eye_coord.w);
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/* Calculate the fog amount per-vertex and interpolate it for
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the fragment shader */
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if (fog_mode == GL_EXP)
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fog_amount = exp (-fog_density * fog_coord);
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else if (fog_mode == GL_EXP2)
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fog_amount = exp (-fog_density * fog_coord
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* fog_density * fog_coord);
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else
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fog_amount = (fog_end - fog_coord) / (fog_end - fog_start);
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fog_amount = clamp (fog_amount, 0.0, 1.0);
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}
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}
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