void LoadTextures()
{
// Generate textures
GLES20.GlGenTextures(2, _textures, 0);
// Load input bitmap
var bitmap = BitmapFactory.DecodeResource(Resources, Resource.Drawable.Lenna);
_imageWidth = bitmap.Width;
_imageHeight = bitmap.Height;
Renderer.UpdateTextureSize(_imageWidth, _imageHeight);
// Upload to texture
GLES20.GlBindTexture(GLES20.GlTexture2d, _textures [0]);
GLUtils.TexImage2D(GLES20.GlTexture2d, 0, bitmap, 0);
// Set texture parameters
GLToolbox.InitTexParams();
}
public void RenderTexture(int texId)
{
// Bind default FBO
GLES20.GlBindFramebuffer(GLES20.GlFramebuffer, 0);
// Use our shader program
GLES20.GlUseProgram(_program);
GLToolbox.CheckGLError("glUseProgram");
// Set viewport
GLES20.GlViewport(0, 0, _viewWidth, _viewHeight);
GLToolbox.CheckGLError("glViewport");
// Disable blending
GLES20.GlDisable(GLES20.GlBlend);
// Set the vertex attributes
GLES20.GlVertexAttribPointer(_texCoordHandle, 2, GLES20.GlFloat, false,
0, _texVertices);
GLES20.GlEnableVertexAttribArray(_texCoordHandle);
GLES20.GlVertexAttribPointer(_posCoordHandle, 2, GLES20.GlFloat, false,
0, _posVertices);
GLES20.GlEnableVertexAttribArray(_posCoordHandle);
GLToolbox.CheckGLError("vertex attribute setup");
// Set the input texture
GLES20.GlActiveTexture(GLES20.GlTexture0);
GLToolbox.CheckGLError("glActiveTexture");
GLES20.GlBindTexture(GLES20.GlTexture2d, texId);
GLToolbox.CheckGLError("glBindTexture");
GLES20.GlUniform1i(_texSamplerHandle, 0);
// Draw
GLES20.GlClearColor(0.0f, 0.0f, 0.0f, 1.0f);
GLES20.GlClear(GLES20.GlColorBufferBit);
GLES20.GlDrawArrays(GLES20.GlTriangleStrip, 0, 4);
}
public void Init()
{
// Create program
_program = GLToolbox.CreateProgram(VertexShader, FragmentShader);
// Bind attributes and uniforms
_texSamplerHandle = GLES20.GlGetUniformLocation(_program,
"tex_sampler");
_texCoordHandle = GLES20.GlGetAttribLocation(_program, "a_texcoord");
_posCoordHandle = GLES20.GlGetAttribLocation(_program, "a_position");
// Setup coordinate buffers
_texVertices = ByteBuffer.AllocateDirect(
TexVertices.Length * FloatSizeBytes)
.Order(ByteOrder.NativeOrder()).AsFloatBuffer();
_texVertices.Put(TexVertices).Position(0);
_posVertices = ByteBuffer.AllocateDirect(
PosVertices.Length * FloatSizeBytes)
.Order(ByteOrder.NativeOrder()).AsFloatBuffer();
_posVertices.Put(PosVertices).Position(0);
}
