1 files changed, 389 insertions, 0 deletions
diff --git a/dev/MinGfx/src/shader_program.cc b/dev/MinGfx/src/shader_program.cc
new file mode 100644
index 0000000..faeb82e
--- /dev/null
+++ b/dev/MinGfx/src/shader_program.cc
@@ -0,0 +1,389 @@
+/*
+ Copyright (c) 2017,2018 Regents of the University of Minnesota.
+ All Rights Reserved.
+ See corresponding header file for details.
+ */
+
+#include "shader_program.h"
+
+#include "opengl_headers.h"
+
+#include <vector>
+#include <fstream>
+
+
+namespace mingfx {
+
+
+ShaderProgram::ShaderProgram() : vertexShader_(0), fragmentShader_(0), program_(0) {
+}
+
+ShaderProgram::~ShaderProgram() {
+}
+    
+bool ShaderProgram::initialized() {
+    return (program_ != 0);
+}
+
+bool ShaderProgram::AddVertexShaderFromSource(const std::string &vertexSource) {
+    // https://www.khronos.org/opengl/wiki/Shader_Compilation
+    
+    // Create an empty vertex shader handle
+    vertexShader_ = glCreateShader(GL_VERTEX_SHADER);
+    
+    // Send the vertex shader source code to GL
+    // Note that std::string's .c_str is NULL character terminated.
+    const GLchar *source = (const GLchar *)vertexSource.c_str();
+    glShaderSource(vertexShader_, 1, &source, 0);
+    
+    // Compile the vertex shader
+    glCompileShader(vertexShader_);
+    
+    GLint isCompiled = 0;
+    glGetShaderiv(vertexShader_, GL_COMPILE_STATUS, &isCompiled);
+    if (isCompiled == GL_FALSE) {
+        GLint maxLength = 0;
+        glGetShaderiv(vertexShader_, GL_INFO_LOG_LENGTH, &maxLength);
+        
+        // The maxLength includes the NULL character
+        std::vector<GLchar> infoLog(maxLength);
+        glGetShaderInfoLog(vertexShader_, maxLength, &maxLength, &infoLog[0]);
+        
+        // We don't need the shader anymore.
+        glDeleteShader(vertexShader_);
+        
+        std::cerr << "ShaderProgram: Error compiling vertex shader program: " << std::endl;
+        std::cerr << &infoLog[0] << std::endl;
+        std::cerr << vertexSource << std::endl;
+        return false;
+    }
+    return true;
+}
+    
+bool ShaderProgram::AddVertexShaderFromFile(const std::string &file) {
+    std::cout << "Loading vertex shader from file: " << file << std::endl;
+    std::string source;
+    std::string line;
+    std::ifstream myfile (file);
+    if (myfile.is_open()) {
+        while (std::getline(myfile, line)) {
+            source += line + "\n";
+        }
+        myfile.close();
+        return AddVertexShaderFromSource(source);
+    }
+    else {
+        std::cerr << "ShaderProgram: Cannot open file " << file << std::endl;
+        return false;
+    }
+}
+
+    
+    
+bool ShaderProgram::AddFragmentShaderFromSource(const std::string &fragmentSource) {
+    // https://www.khronos.org/opengl/wiki/Shader_Compilation
+    
+    // Create an empty fragment shader handle
+    fragmentShader_ = glCreateShader(GL_FRAGMENT_SHADER);
+    
+    // Send the fragment shader source code to GL
+    // Note that std::string's .c_str is NULL character terminated.
+    const GLchar *source = (const GLchar *)fragmentSource.c_str();
+    glShaderSource(fragmentShader_, 1, &source, 0);
+    
+    // Compile the fragment shader
+    glCompileShader(fragmentShader_);
+    
+    GLint isCompiled = 0;
+    glGetShaderiv(fragmentShader_, GL_COMPILE_STATUS, &isCompiled);
+    if (isCompiled == GL_FALSE) {
+        GLint maxLength = 0;
+        glGetShaderiv(fragmentShader_, GL_INFO_LOG_LENGTH, &maxLength);
+        
+        // The maxLength includes the NULL character
+        std::vector<GLchar> infoLog(maxLength);
+        glGetShaderInfoLog(fragmentShader_, maxLength, &maxLength, &infoLog[0]);
+        
+        // We don't need the shader anymore.
+        glDeleteShader(fragmentShader_);
+        
+        std::cerr << "ShaderProgram: Error compiling fragment shader program: " << std::endl;
+        std::cerr << &infoLog[0] << std::endl;
+        std::cerr << fragmentSource << std::endl;
+        return false;
+    }
+    return true;
+}
+
+
+bool ShaderProgram::AddFragmentShaderFromFile(const std::string &file) {
+    std::cout << "Loading fragment shader from file: " << file << std::endl;
+    std::string source;
+    std::string line;
+    std::ifstream myfile (file);
+    if (myfile.is_open()) {
+        while (std::getline(myfile, line)) {
+            source += line + "\n";
+        }
+        myfile.close();
+        return AddFragmentShaderFromSource(source);
+    }
+    else {
+        std::cerr << "ShaderProgram: Cannot open file " << file << std::endl;
+        return false;
+    }
+}
+
+    
+bool ShaderProgram::LinkProgram() {
+    if (!vertexShader_) {
+        std::cerr << "ShaderProgram: Error linking program.  A vertex shader must be added and successfully compiled before the program can be linked." << std::endl;
+        return false;
+    }
+    if (!fragmentShader_) {
+        std::cerr << "ShaderProgram: Error linking program.  A fragment shader must be added and successfully compiled before the program can be linked." << std::endl;
+        return false;
+    }
+    
+    // Vertex and fragment shaders are successfully compiled.
+    // Now time to link them together into a program.
+    // Get a program object.
+    program_ = glCreateProgram();
+    
+    // Attach our shaders to our program
+    glAttachShader(program_, vertexShader_);
+    glAttachShader(program_, fragmentShader_);
+    
+    // Link our program
+    glLinkProgram(program_);
+    
+    // Note the different functions here: glGetProgram* instead of glGetShader*.
+    GLint isLinked = 0;
+    glGetProgramiv(program_, GL_LINK_STATUS, (int *)&isLinked);
+    if (isLinked == GL_FALSE) {
+        GLint maxLength = 0;
+        glGetProgramiv(program_, GL_INFO_LOG_LENGTH, &maxLength);
+        
+        // The maxLength includes the NULL character
+        std::vector<GLchar> infoLog(maxLength);
+        glGetProgramInfoLog(program_, maxLength, &maxLength, &infoLog[0]);
+        
+        // We don't need the program anymore.
+        glDeleteProgram(program_);
+        // Don't leak shaders either.
+        glDeleteShader(vertexShader_);
+        glDeleteShader(fragmentShader_);
+        
+        std::cerr << "ShaderProgram: Error linking program: " << std::endl;
+        std::cerr << &infoLog[0] << std::endl;
+        return false;
+    }
+    
+    // Always detach shaders after a successful link.
+    glDetachShader(program_, vertexShader_);
+    glDetachShader(program_, fragmentShader_);
+    
+    return true;
+}
+    
+
+void ShaderProgram::UseProgram() {
+    if (!initialized()) {
+        std::cerr << "ShaderProgram: Warning cannot UseProgram() until it shaders have been added and linked.  Calling LinkProgram() for you now." << std::endl;
+        LinkProgram();
+    }
+    glUseProgram(program_);
+}
+
+    
+void ShaderProgram::StopProgram() {
+    glUseProgram(0);
+}
+    
+    
+// MinGfx math types
+void ShaderProgram::SetUniform(const std::string &name, const Point2 &p) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform2f(loc, p[0], p[1]);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, const Vector2 &v) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform2f(loc, v[0], v[1]);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, const Point3 &p) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform3f(loc, p[0], p[1], p[2]);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, const Vector3 &v) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform3f(loc, v[0], v[1], v[2]);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, const Matrix4 &m) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniformMatrix4fv(loc, 1, GL_FALSE, m.value_ptr());
+}
+
+void ShaderProgram::SetUniform(const std::string &name, const Color &c) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform4f(loc, c[0], c[1], c[2], c[3]);
+}
+    
+
+// built-in types
+void ShaderProgram::SetUniform(const std::string &name, int i) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1i(loc, i);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, unsigned int ui) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1ui(loc, ui);
+}
+
+void ShaderProgram::SetUniform(const std::string &name, float f) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1f(loc, f);
+}
+
+
+
+// built-in types - arrays
+void ShaderProgram::SetUniformArray1(const std::string &name, int *i, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1iv(loc, count, i);
+}
+
+void ShaderProgram::SetUniformArray1(const std::string &name, unsigned int *ui, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1uiv(loc, count, ui);
+}
+
+void ShaderProgram::SetUniformArray1(const std::string &name, float *f, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1fv(loc, count, f);
+}
+
+
+void ShaderProgram::SetUniformArray2(const std::string &name, int *i, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform2iv(loc, count, i);
+}
+
+void ShaderProgram::SetUniformArray2(const std::string &name, unsigned int *ui, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform2uiv(loc, count, ui);
+}
+
+void ShaderProgram::SetUniformArray2(const std::string &name, float *f, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform2fv(loc, count, f);
+}
+
+
+void ShaderProgram::SetUniformArray3(const std::string &name, int *i, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform3iv(loc, count, i);
+}
+
+void ShaderProgram::SetUniformArray3(const std::string &name, unsigned int *ui, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform3uiv(loc, count, ui);
+}
+
+void ShaderProgram::SetUniformArray3(const std::string &name, float *f, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform3fv(loc, count, f);
+}
+
+
+void ShaderProgram::SetUniformArray4(const std::string &name, int *i, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform4iv(loc, count, i);
+}
+
+void ShaderProgram::SetUniformArray4(const std::string &name, unsigned int *ui, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform4uiv(loc, count, ui);
+}
+
+void ShaderProgram::SetUniformArray4(const std::string &name, float *f, int count) {
+    UseProgram();
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform4fv(loc, count, f);
+}
+
+
+
+void ShaderProgram::BindTexture(const std::string &name, const Texture2D &tex) {
+    UseProgram();
+
+    int texUnit = 0;
+    
+    std::map<std::string,int>::const_iterator it = texBindings_.find(name);
+    if (it != texBindings_.end()) {
+        // Found: This sampler was already bound to a tex unit, so use the same one
+        texUnit = texBindings_[name];
+    }
+    else {
+        // Not found: This sampler was not already bound to a tex unit, so loop through the
+        // past/current bindings and pick the next available texUnit
+        std::map<std::string,int>::const_iterator it2;
+        for (it2 = texBindings_.begin(); it2 != texBindings_.end(); ++it2) {
+            if (texUnit <= it2->second) {
+                texUnit = it2->second + 1;
+            }
+        }
+        // save it for future reference
+        texBindings_[name] = texUnit;
+    }
+    
+    // associate the named shader program sampler variable with the selected texture unit
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1i(loc, texUnit);
+    // bind the opengl texture handle to the same texture unit
+    glActiveTexture(GL_TEXTURE0 + texUnit);
+    glBindTexture(GL_TEXTURE_2D, tex.opengl_id());
+}
+
+void ShaderProgram::BindTexture(const std::string &name, const Texture2D &tex, int texUnit) {
+    UseProgram();
+
+    texBindings_[name] = texUnit;
+    
+    // associate the named shader program sampler variable with the selected texture unit
+    GLint loc = glGetUniformLocation(program_, name.c_str());
+    glUniform1i(loc, texUnit);
+    // bind the opengl texture handle to the same texture unit
+    glActiveTexture(GL_TEXTURE0 + texUnit);
+    glBindTexture(GL_TEXTURE_2D, tex.opengl_id());
+}
+
+
+    
+} // end namespace
+
+