public void Draw()
{
Gles.glEnable(Gles.GL_DEPTH_TEST);
Gles.glClear(Gles.GL_COLOR_BUFFER_BIT | Gles.GL_DEPTH_BUFFER_BIT);
if (mProgram == 0)
{
return;
}
Gles.glUseProgram(mProgram);
Gles.glBindBuffer(Gles.GL_ARRAY_BUFFER, mVertexPositionBuffer);
Gles.glEnableVertexAttribArray((GLuint)mPositionAttribLocation);
Gles.glVertexAttribPointer((GLuint)mPositionAttribLocation, 3, Gles.GL_FLOAT, Gles.GL_FALSE, 0, IntPtr.Zero);
Gles.glBindBuffer(Gles.GL_ARRAY_BUFFER, mVertexColorBuffer);
Gles.glEnableVertexAttribArray((GLuint)mColorAttribLocation);
Gles.glVertexAttribPointer((GLuint)mColorAttribLocation, 3, Gles.GL_FLOAT, Gles.GL_FALSE, 0, IntPtr.Zero);
float[,] modelMatrix = MathHelpers.SimpleModelMatrix((float)mDrawCount / 50.0f);
Gles.glUniformMatrix4fv(mModelUniformLocation, 1, Gles.GL_FALSE, modelMatrix);
float[,] viewMatrix = MathHelpers.SimpleViewMatrix();
Gles.glUniformMatrix4fv(mViewUniformLocation, 1, Gles.GL_FALSE, viewMatrix);
float[,] projectionMatrix = MathHelpers.SimpleProjectionMatrix((float)mWindowWidth / (float)mWindowHeight);
Gles.glUniformMatrix4fv(mProjUniformLocation, 1, Gles.GL_FALSE, projectionMatrix);
// Draw 36 indices: six faces, two triangles per face, 3 indices per triangle
Gles.glBindBuffer(Gles.GL_ELEMENT_ARRAY_BUFFER, mIndexBuffer);
Gles.glDrawElements(Gles.GL_TRIANGLES, (6 * 2) * 3, Gles.GL_UNSIGNED_SHORT, IntPtr.Zero);
mDrawCount += 1;
}
public void Dispose()
{
if (mProgram != 0)
{
Gles.glDeleteProgram(mProgram);
mProgram = 0;
}
if (mVertexPositionBuffer != 0)
{
Gles.glDeleteBuffers(1, ref mVertexPositionBuffer);
mVertexPositionBuffer = 0;
}
if (mVertexColorBuffer != 0)
{
Gles.glDeleteBuffers(1, ref mVertexColorBuffer);
mVertexColorBuffer = 0;
}
if (mIndexBuffer != 0)
{
Gles.glDeleteBuffers(1, ref mIndexBuffer);
mIndexBuffer = 0;
}
}
public static void glThrowError()
{
var error = Gles.glGetError();
if (error != 0)
{
throw new Exception("OpenGL ES error: 0x" + error.ToString("x").PadLeft(4, '0'));
}
}
private static GLuint CompileProgram(string vsSource, string fsSource)
{
GLuint program = Gles.glCreateProgram();
if (program == 0)
{
throw new Exception("Program creation failed");
}
GLuint vs = CompileShader(Gles.GL_VERTEX_SHADER, vsSource);
GLuint fs = CompileShader(Gles.GL_FRAGMENT_SHADER, fsSource);
if (vs == 0 || fs == 0)
{
Gles.glDeleteShader(fs);
Gles.glDeleteShader(vs);
Gles.glDeleteProgram(program);
return(0);
}
Gles.glAttachShader(program, vs);
Gles.glDeleteShader(vs);
Gles.glAttachShader(program, fs);
Gles.glDeleteShader(fs);
Gles.glLinkProgram(program);
Gles.glGetProgramiv(program, Gles.GL_LINK_STATUS, out GLint linkStatus);
if (linkStatus == 0)
{
Gles.glGetProgramiv(program, Gles.GL_INFO_LOG_LENGTH, out GLint infoLogLength);
StringBuilder infoLog = new StringBuilder(infoLogLength);
Gles.glGetProgramInfoLog(program, (GLsizei)infoLog.Capacity, out GLsizei length, infoLog);
string errorMessage = "Program link failed: " + infoLog;
throw new Exception(errorMessage);
}
return(program);
}
private static GLuint CompileShader(GLenum type, string source)
{
GLuint shader = Gles.glCreateShader(type);
Gles.glShaderSource(shader, 1, new[] { source }, new[] { source.Length });
Gles.glCompileShader(shader);
Gles.glGetShaderiv(shader, Gles.GL_COMPILE_STATUS, out GLint compileResult);
if (compileResult == 0)
{
Gles.glGetShaderiv(shader, Gles.GL_INFO_LOG_LENGTH, out GLint infoLogLength);
StringBuilder infoLog = new StringBuilder(infoLogLength);
Gles.glGetShaderInfoLog(shader, (GLsizei)infoLog.Capacity, out GLsizei length, infoLog);
string errorMessage = "Shader compilation failed: " + infoLog;
throw new Exception(errorMessage);
}
return(shader);
}
public SimpleRenderer()
{
mWindowWidth = 0;
mWindowHeight = 0;
mDrawCount = 0;
// Vertex Shader source
string vs =
@"uniform mat4 uModelMatrix;
uniform mat4 uViewMatrix;
uniform mat4 uProjMatrix;
attribute vec4 aPosition;
attribute vec4 aColor;
varying vec4 vColor;
void main()
{
gl_Position = uProjMatrix * uViewMatrix * uModelMatrix * aPosition;
vColor = aColor;
}";
// Fragment Shader source
string fs =
@"precision mediump float;
varying vec4 vColor;
void main()
{
gl_FragColor = vColor;
}";
// Set up the shader and its uniform/attribute locations.
mProgram = CompileProgram(vs, fs);
mPositionAttribLocation = Gles.glGetAttribLocation(mProgram, "aPosition");
mColorAttribLocation = Gles.glGetAttribLocation(mProgram, "aColor");
mModelUniformLocation = Gles.glGetUniformLocation(mProgram, "uModelMatrix");
mViewUniformLocation = Gles.glGetUniformLocation(mProgram, "uViewMatrix");
mProjUniformLocation = Gles.glGetUniformLocation(mProgram, "uProjMatrix");
// Then set up the cube geometry.
GLfloat[] vertexPositions = new[]
{
-1.0f, -1.0f, -1.0f,
-1.0f, -1.0f, 1.0f,
-1.0f, 1.0f, -1.0f,
-1.0f, 1.0f, 1.0f,
1.0f, -1.0f, -1.0f,
1.0f, -1.0f, 1.0f,
1.0f, 1.0f, -1.0f,
1.0f, 1.0f, 1.0f,
};
Gles.glGenBuffers(1, out mVertexPositionBuffer);
Gles.glBindBuffer(Gles.GL_ARRAY_BUFFER, mVertexPositionBuffer);
Gles.glBufferData(Gles.GL_ARRAY_BUFFER, vertexPositions, Gles.GL_STATIC_DRAW);
GLfloat[] vertexColors = new[]
{
0.0f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f,
0.0f, 1.0f, 0.0f,
0.0f, 1.0f, 1.0f,
1.0f, 0.0f, 0.0f,
1.0f, 0.0f, 1.0f,
1.0f, 1.0f, 0.0f,
1.0f, 1.0f, 1.0f,
};
Gles.glGenBuffers(1, out mVertexColorBuffer);
Gles.glBindBuffer(Gles.GL_ARRAY_BUFFER, mVertexColorBuffer);
Gles.glBufferData(Gles.GL_ARRAY_BUFFER, vertexColors, Gles.GL_STATIC_DRAW);
GLshort[] indices = new GLshort[]
{
0, 1, 2, // -x
1, 3, 2,
4, 6, 5, // +x
5, 6, 7,
0, 5, 1, // -y
0, 4, 5,
2, 7, 6, // +y
2, 3, 7,
0, 6, 4, // -z
0, 2, 6,
1, 7, 3, // +z
1, 5, 7,
};
Gles.glGenBuffers(1, out mIndexBuffer);
Gles.glBindBuffer(Gles.GL_ELEMENT_ARRAY_BUFFER, mIndexBuffer);
Gles.glBufferData(Gles.GL_ELEMENT_ARRAY_BUFFER, indices, Gles.GL_STATIC_DRAW);
}
public void UpdateWindowSize(GLsizei width, GLsizei height)
{
Gles.glViewport(0, 0, width, height);
mWindowWidth = width;
mWindowHeight = height;
}
