Graphics Reference
In-Depth Information
• Compute the fog factor passed to the fragment shader. The fragment
shader uses the fog factor to interpolate between fog color and vertex
color.
• Compute the per-vertex user clip plane factor. Only one user clip
plane is supported.
• Transform the position to clip space.
Example 8-9 is the vertex shader that implements the OpenGL ES 1.1
fixed-function vertex pipeline as already described.
Example 8-9
OpenGL ES 1.1 Fixed-Function Vertex Pipeline
#version 300 es
//**************************************************************
//
// OpenGL ES 3.0 vertex shader that implements the following
// OpenGL ES 1.1 fixed-function pipeline
//
// - compute lighting equation for up to eight
// directional/point/spotlights
// - transform position to clip coordinates
// - texture coordinate transforms for up to two texture
// coordinates
// - compute fog factor
// - compute user clip plane dot product (stored as
// v_ucp_factor)
//
//**************************************************************
#define NUM_TEXTURES 2
#define GLI_FOG_MODE_LINEAR 0
#define GLI_FOG_MODE_EXP 1
#define GLI_FOG_MODE_EXP2 2
struct light
{
vec4 position; // light position for a point/spotlight or
// normalized dir. for a directional light
vec4 ambient_color;
vec4 diffuse_color;
vec4 specular_color;
vec3 spot_direction;
vec3 attenuation_factors;
float spot_exponent;
float spot_cutoff_angle;
bool compute_distance_attenuation;
};
