| // |
| // Copyright (c) 2014 The ANGLE Project Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| // |
| |
| // Based on MipMap2D.c from |
| // Book: OpenGL(R) ES 2.0 Programming Guide |
| // Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner |
| // ISBN-10: 0321502795 |
| // ISBN-13: 9780321502797 |
| // Publisher: Addison-Wesley Professional |
| // URLs: http://safari.informit.com/9780321563835 |
| // http://www.opengles-book.com |
| |
| #include "SampleApplication.h" |
| #include "shader_utils.h" |
| #include "texture_utils.h" |
| |
| class MipMap2DSample : public SampleApplication |
| { |
| public: |
| MipMap2DSample() |
| : SampleApplication("MipMap2D", 1280, 720) |
| { |
| } |
| |
| virtual bool initialize() |
| { |
| const std::string vs = SHADER_SOURCE |
| ( |
| uniform float u_offset; |
| attribute vec4 a_position; |
| attribute vec2 a_texCoord; |
| varying vec2 v_texCoord; |
| void main() |
| { |
| gl_Position = a_position; |
| gl_Position.x += u_offset; |
| v_texCoord = a_texCoord; |
| } |
| ); |
| |
| const std::string fs = SHADER_SOURCE |
| ( |
| precision mediump float; |
| varying vec2 v_texCoord; |
| uniform sampler2D s_texture; |
| void main() |
| { |
| gl_FragColor = texture2D(s_texture, v_texCoord); |
| } |
| ); |
| |
| mProgram = CompileProgram(vs, fs); |
| if (!mProgram) |
| { |
| return false; |
| } |
| |
| // Get the attribute locations |
| mPositionLoc = glGetAttribLocation(mProgram, "a_position"); |
| mTexCoordLoc = glGetAttribLocation(mProgram, "a_texCoord"); |
| |
| // Get the sampler location |
| mSamplerLoc = glGetUniformLocation(mProgram, "s_texture"); |
| |
| // Get the offset location |
| mOffsetLoc = glGetUniformLocation(mProgram, "u_offset"); |
| |
| // Load the texture |
| mTextureID = CreateMipMappedTexture2D(); |
| |
| // Check Anisotropy limits |
| glGetFloatv(GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT, &mMaxAnisotropy); |
| |
| glClearColor(0.0f, 0.0f, 0.0f, 0.0f); |
| |
| return true; |
| } |
| |
| virtual void destroy() |
| { |
| glDeleteProgram(mProgram); |
| glDeleteTextures(1, &mTextureID); |
| } |
| |
| virtual void draw() |
| { |
| const GLfloat vertices[] = |
| { |
| -0.25f, 0.5f, 0.0f, 5.0f, // Position 0 |
| 0.0f, 0.0f, // TexCoord 0 |
| -0.25f, -0.5f, 0.0f, 1.0f, // Position 1 |
| 0.0f, 1.0f, // TexCoord 1 |
| 0.25f, -0.5f, 0.0f, 1.0f, // Position 2 |
| 1.0f, 1.0f, // TexCoord 2 |
| 0.25f, 0.5f, 0.0f, 5.0f, // Position 3 |
| 1.0f, 0.0f // TexCoord 3 |
| }; |
| const GLushort indices[] = { 0, 1, 2, 0, 2, 3 }; |
| |
| // Set the viewport |
| glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight()); |
| |
| // Clear the color buffer |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| // Use the program object |
| glUseProgram(mProgram); |
| |
| // Load the vertex position |
| glVertexAttribPointer(mPositionLoc, 4, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), vertices); |
| // Load the texture coordinate |
| glVertexAttribPointer(mTexCoordLoc, 2, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), vertices + 4); |
| |
| glEnableVertexAttribArray(mPositionLoc); |
| glEnableVertexAttribArray(mTexCoordLoc); |
| |
| // Bind the texture |
| glActiveTexture(GL_TEXTURE0); |
| glBindTexture(GL_TEXTURE_2D, mTextureID); |
| |
| // Set the sampler texture unit to 0 |
| glUniform1i(mSamplerLoc, 0); |
| |
| // Draw quad with nearest sampling |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); |
| glUniform1f(mOffsetLoc, -0.6f); |
| glDrawElements ( GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices); |
| |
| // Draw quad with trilinear filtering |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); |
| glUniform1f(mOffsetLoc, 0.0f); |
| glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices); |
| |
| // Draw quad with anisotropic filtering |
| glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); |
| glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, mMaxAnisotropy); |
| glUniform1f(mOffsetLoc, 0.6f); |
| glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices); |
| glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT, 1.0f); |
| } |
| |
| private: |
| // Handle to a program object |
| GLuint mProgram; |
| |
| // Attribute locations |
| GLint mPositionLoc; |
| GLint mTexCoordLoc; |
| |
| // Sampler location |
| GLint mSamplerLoc; |
| |
| // Offset location |
| GLint mOffsetLoc; |
| |
| // Texture handle |
| GLuint mTextureID; |
| |
| float mMaxAnisotropy; |
| }; |
| |
| int main(int argc, char **argv) |
| { |
| MipMap2DSample app; |
| return app.run(); |
| } |