private void InitShaders()
{
// create our shaders
WebGLShader vertexShader = LoadShader(GLES20.VERTEX_SHADER, @"
attribute vec4 a_position;
attribute vec4 a_color;
attribute vec2 a_texCoord0;
attribute vec2 a_texCoord1;
uniform mat4 u_mvpMatrix;
varying vec4 v_color;
varying vec2 v_texCoord0;
varying vec2 v_texCoord1;
void main()
{
gl_Position = u_mvpMatrix * a_position;
v_color = a_color;
v_texCoord0 = a_texCoord0;
v_texCoord1 = a_texCoord1;
}");
WebGLShader fragmentShader = LoadShader(GLES20.FRAGMENT_SHADER, @"
#ifdef GL_ES
precision mediump float;
#endif
uniform sampler2D s_texture0;
uniform sampler2D s_texture1;
uniform int s_texEnv0;
uniform int s_texEnv1;
uniform int u_enable_texture_0;
uniform int u_enable_texture_1;
varying vec4 v_color;
varying vec2 v_texCoord0;
varying vec2 v_texCoord1;
vec4 finalColor;
void main()
{
finalColor = v_color;
if (u_enable_texture_0 == 1)
{
vec4 texel = texture2D(s_texture0, v_texCoord0);
if (s_texEnv0 == 1) {
finalColor = finalColor * texel;
} else if (s_texEnv0 == 2) {
finalColor = vec4(texel.r, texel.g, texel.b, finalColor.a);
} else {
finalColor = texel;
}
}
if (u_enable_texture_1 == 1) {
vec4 texel = texture2D(s_texture1, v_texCoord1);
if (s_texEnv1 == 1) {
finalColor = finalColor * texel;
} else if (s_texEnv1 == 2) {
finalColor = vec4(texel.r, texel.g, texel.b, finalColor.a);
} else {
finalColor = texel;
}
}
// simple alpha check
if (finalColor.a == 0.0) {
discard;
}
float gamma = 1.5;
float igamma = 1.0 / gamma;
gl_FragColor = vec4(pow(finalColor.r, igamma), pow(finalColor.g, igamma), pow(finalColor.b, igamma), finalColor.a);
}");
if ((vertexShader == null) || (fragmentShader == null))
{
throw new Exception("RuntimeException: shader error");
}
// Create the program object
WebGLProgram programObject = gl.CreateProgram();
if ((programObject == null) || (gl.GetError() != GLES20.NO_ERROR))
{
throw new Exception("RuntimeException: program error");
}
// Attach our two shaders to the program
gl.AttachShader(programObject, vertexShader);
gl.AttachShader(programObject, fragmentShader);
// Bind "vPosition" to attribute 0
gl.BindAttribLocation(programObject, ARRAY_POSITION, "a_position");
gl.BindAttribLocation(programObject, ARRAY_COLOR, "a_color");
gl.BindAttribLocation(programObject, ARRAY_TEXCOORD_0, "a_texCoord0");
gl.BindAttribLocation(programObject, ARRAY_TEXCOORD_1, "a_texCoord1");
// Link the program
gl.LinkProgram(programObject);
// TODO(haustein) get position, color from the linker, too
_uMvpMatrix = gl.GetUniformLocation(programObject, "u_mvpMatrix");
_uSampler0 = gl.GetUniformLocation(programObject, "s_texture0");
_uSampler1 = gl.GetUniformLocation(programObject, "s_texture1");
_uTexEnv0 = gl.GetUniformLocation(programObject, "s_texEnv0");
_uTexEnv1 = gl.GetUniformLocation(programObject, "s_texEnv1");
_uEnableTexture0 = gl.GetUniformLocation(programObject, "u_enable_texture_0");
_uEnableTexture1 = gl.GetUniformLocation(programObject, "u_enable_texture_1");
// Check the link status
bool linked = (bool)gl.GetProgramParameter(programObject, GLES20.LINK_STATUS);
if (!linked)
{
throw new Exception("RuntimeException: linker Error: " + gl.GetProgramInfoLog(programObject));
}
gl.UseProgram(programObject);
gl.Uniform1i(_uSampler0, 0);
gl.Uniform1i(_uSampler1, 1);
gl.ActiveTexture(GLES20.TEXTURE0);
}
