зеркало из https://github.com/AvaloniaUI/angle.git
144 строки
3.9 KiB
C++
144 строки
3.9 KiB
C++
//
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// Copyright 2014 The ANGLE Project Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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//
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// Based on Simple_VertexShader.c from
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// Book: OpenGL(R) ES 2.0 Programming Guide
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// Authors: Aaftab Munshi, Dan Ginsburg, Dave Shreiner
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// ISBN-10: 0321502795
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// ISBN-13: 9780321502797
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// Publisher: Addison-Wesley Professional
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// URLs: http://safari.informit.com/9780321563835
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// http://www.opengles-book.com
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#include "SampleApplication.h"
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#include "texture_utils.h"
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#include "util/Matrix.h"
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#include "util/geometry_utils.h"
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#include "util/shader_utils.h"
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#include <cmath>
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class SimpleVertexShaderSample : public SampleApplication
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{
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public:
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SimpleVertexShaderSample(int argc, char **argv)
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: SampleApplication("SimpleVertexShader", argc, argv)
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{}
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bool initialize() override
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{
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constexpr char kVS[] = R"(uniform mat4 u_mvpMatrix;
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attribute vec4 a_position;
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attribute vec2 a_texcoord;
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varying vec2 v_texcoord;
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void main()
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{
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gl_Position = u_mvpMatrix * a_position;
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v_texcoord = a_texcoord;
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})";
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constexpr char kFS[] = R"(precision mediump float;
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varying vec2 v_texcoord;
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void main()
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{
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gl_FragColor = vec4(v_texcoord.x, v_texcoord.y, 1.0, 1.0);
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})";
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mProgram = CompileProgram(kVS, kFS);
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if (!mProgram)
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{
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return false;
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}
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// Get the attribute locations
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mPositionLoc = glGetAttribLocation(mProgram, "a_position");
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mTexcoordLoc = glGetAttribLocation(mProgram, "a_texcoord");
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// Get the uniform locations
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mMVPMatrixLoc = glGetUniformLocation(mProgram, "u_mvpMatrix");
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// Generate the geometry data
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GenerateCubeGeometry(0.5f, &mCube);
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// Set an initial rotation
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mRotation = 45.0f;
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glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
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glCullFace(GL_BACK);
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glEnable(GL_CULL_FACE);
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return true;
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}
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void destroy() override { glDeleteProgram(mProgram); }
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void step(float dt, double totalTime) override
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{
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mRotation = fmod(mRotation + (dt * 40.0f), 360.0f);
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Matrix4 perspectiveMatrix = Matrix4::perspective(
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60.0f, float(getWindow()->getWidth()) / getWindow()->getHeight(), 1.0f, 20.0f);
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Matrix4 modelMatrix = Matrix4::translate(angle::Vector3(0.0f, 0.0f, -2.0f)) *
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Matrix4::rotate(mRotation, angle::Vector3(1.0f, 0.0f, 1.0f));
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Matrix4 viewMatrix = Matrix4::identity();
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Matrix4 mvpMatrix = perspectiveMatrix * viewMatrix * modelMatrix;
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// Load the matrices
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glUniformMatrix4fv(mMVPMatrixLoc, 1, GL_FALSE, mvpMatrix.data);
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}
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void draw() override
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{
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// Set the viewport
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glViewport(0, 0, getWindow()->getWidth(), getWindow()->getHeight());
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// Clear the color buffer
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glClear(GL_COLOR_BUFFER_BIT);
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// Use the program object
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glUseProgram(mProgram);
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// Load the vertex position
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glVertexAttribPointer(mPositionLoc, 3, GL_FLOAT, GL_FALSE, 0, mCube.positions.data());
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glEnableVertexAttribArray(mPositionLoc);
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// Load the texcoord data
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glVertexAttribPointer(mTexcoordLoc, 2, GL_FLOAT, GL_FALSE, 0, mCube.texcoords.data());
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glEnableVertexAttribArray(mTexcoordLoc);
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// Draw the cube
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glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(mCube.indices.size()), GL_UNSIGNED_SHORT,
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mCube.indices.data());
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}
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private:
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// Handle to a program object
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GLuint mProgram;
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// Attribute locations
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GLint mPositionLoc;
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GLint mTexcoordLoc;
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// Uniform locations
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GLuint mMVPMatrixLoc;
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// Current rotation
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float mRotation;
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// Geometry data
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CubeGeometry mCube;
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};
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int main(int argc, char **argv)
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{
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SimpleVertexShaderSample app(argc, argv);
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return app.run();
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}
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