public void Init(Size size)
{
OpenGLMaterial.InitCommonMaterials();
// Other state
GL.Disable(GL.GL_CULL_FACE);
GL.Disable(GL.GL_DEPTH_TEST);
GL.DepthFunc(GL.GL_NEVER);
GL.Enable(GL.GL_SCISSOR_TEST);
InitializeTextRenderResources(size);
}
static OpenGLMaterial()
{
//On linux we use EGL to create OpenGLES 3.x context instead of OpenGL 3.x context.
//See LinuxOpenGLRenderer.CreateEGLContext()
//So the shader version should be "300 es" for linux OS.
string versionHeader = (OperatingSystem.IsAndroid() || OperatingSystem.IsLinux())
? "#version 300 es" : "#version 330";
shapeVertexShaderText = versionHeader + @"
precision mediump float;
uniform mat4 ProjMtx;
uniform mat4 ViewMtx;
in vec2 Position;
in vec2 UV;
in vec4 Color;
out vec2 Frag_UV;
out vec4 Frag_Color;
void main()
{
Frag_UV = UV;
Frag_Color = Color;
gl_Position = ProjMtx * ViewMtx * vec4(Position.xy,0,1);
}
";
shapeFragmentShader = versionHeader + @"
precision mediump float;
uniform sampler2D Texture;
in vec2 Frag_UV;
in vec4 Frag_Color;
out vec4 Out_Color;
void main()
{
Out_Color = Frag_Color;
}
";
imageVertexShader = versionHeader + @"
precision mediump float;
uniform mat4 ProjMtx;
uniform mat4 ViewMtx;
in vec2 Position;
in vec2 UV;
in vec4 Color;
out vec2 Frag_UV;
out vec4 Frag_Color;
void main()
{
Frag_UV = UV;
Frag_Color = Color;
gl_Position = ProjMtx * ViewMtx * vec4(Position.xy,0,1);
}
";
textVertexShader = versionHeader + @"
precision mediump float;
in vec2 Position;
in vec2 UV;
in vec4 Color;
out vec2 Frag_UV;
out vec4 Frag_Color;
void main()
{
Frag_UV = UV;
Frag_Color = Color;
//directly assigned to gl_Position: the clip-space output position of the current vertex.
gl_Position = vec4(Position, 0.0, 1.0);
}
";
imageFragmentShader = versionHeader + @"
precision mediump float;
uniform sampler2D Texture;
in vec2 Frag_UV;
in vec4 Frag_Color;
out vec4 Out_Color;
void main()
{
Out_Color = Frag_Color * texture( Texture, Frag_UV.st);
}
";
glyphVertexShader = versionHeader + @"
precision mediump float;
uniform mat4 ProjMtx;
uniform mat4 ViewMtx;
in vec2 Position;
in vec2 UV;
in vec4 Color;
out vec2 Frag_UV;
out vec4 Frag_Color;
uniform vec2 offset;
void main()
{
Frag_UV = UV;
Frag_Color = Color;//dummy Frag_Color is useless
gl_Position = ProjMtx * ViewMtx * vec4(offset+Position.xy,0,1);
}
";
glyphFragmentShader = versionHeader + @"
precision mediump float;
in vec2 Frag_UV;
in vec4 Frag_Color;
out vec4 Out_Color;
uniform vec4 color;
void main()
{
if (Frag_UV.s * Frag_UV.s - Frag_UV.t > 0.0)
{
discard;
}
// Upper 4 bits: front faces
// Lower 4 bits: back faces
//Out_Color = Frag_Color + color *0.001;
Out_Color = Frag_Color *0.001 + color * (gl_FrontFacing ? 16.0 / 255.0 : 1.0 / 255.0);
}
";
textFragmentShader = versionHeader + @"
precision mediump float;
in vec2 Frag_UV;
in vec4 Frag_Color;
out vec4 Out_Color;
uniform sampler2D Texture;
uniform vec4 color;
void main()
{
// Get samples for -2/3 and -1/3
vec2 valueL = texture(Texture, vec2(Frag_UV.x + dFdx(Frag_UV.x), Frag_UV.y)).yz * 255.0;
vec2 lowerL = mod(valueL, 16.0);
vec2 upperL = (valueL - lowerL) / 16.0;
vec2 alphaL = min(abs(upperL - lowerL), 2.0);
// Get samples for 0, +1/3, and +2/3
vec3 valueR = texture(Texture, Frag_UV).xyz * 255.0;
vec3 lowerR = mod(valueR, 16.0);
vec3 upperR = (valueR - lowerR) / 16.0;
vec3 alphaR = min(abs(upperR - lowerR), 2.0);
// Average the energy over the pixels on either side
vec4 rgba = vec4(
(alphaR.x + alphaR.y + alphaR.z) / 6.0,
(alphaL.y + alphaR.x + alphaR.y) / 6.0,
(alphaL.x + alphaL.y + alphaR.x) / 6.0,
0.0);
Out_Color = 0.0001 * Frag_Color
+ 0.0001 * (color.a == 0.0 ? 1.0 - rgba : color * rgba)
+ 1.0 - rgba;
//TODO This approach only supports black colored text
//NOTE Out_Color's alpha channel is the transparency of the drawn text.
//NOTE A clear color with alpha 0 will make the drawn text invisible!!
//actual code:
//Out_Color = 1.0 - rgba;
}
";
shapeMaterial = new OpenGLMaterial(
vertexShader: shapeVertexShaderText,
fragmentShader: shapeFragmentShader
);
imageMaterial = new OpenGLMaterial(
vertexShader: imageVertexShader,
fragmentShader: imageFragmentShader
);
glyphMaterial = new OpenGLMaterial(
vertexShader: glyphVertexShader,
fragmentShader: glyphFragmentShader
);
textMaterial = new OpenGLMaterial(
vertexShader: textVertexShader,
fragmentShader: textFragmentShader
);
}