Merge branch 'shaders'

1 files changed, 234 insertions, 0 deletions

diff --git a/wave-sim/src/graphics/shader.cpp b/wave-sim/src/graphics/shader.cpp
new file mode 100644
index 0000000..3789be0
--- /dev/null
+++ b/wave-sim/src/graphics/shader.cpp
@@ -0,0 +1,234 @@
+#include "graphics/shader.h"
+#include "graphics/graphicsdebug.h"
+
+#include <QFile>
+#include <QString>
+#include <QTextStream>
+#include <iostream>
+
+Shader::Shader(const std::string &vertexPath,
+               const std::string &fragmentPath)
+{
+    createProgramID();
+
+    std::vector<GLuint> shaders = {
+        createShaderFromString(getFileContents(vertexPath),   GL_VERTEX_SHADER),
+        createShaderFromString(getFileContents(fragmentPath), GL_FRAGMENT_SHADER)
+    };
+
+    buildShaderProgramFromShaders(shaders);
+    discoverShaderData();
+}
+
+Shader::~Shader()
+{
+    glDeleteProgram(m_programID);
+}
+
+Shader::Shader(Shader &&that)
+    : m_programID(that.m_programID),
+      m_attributes(std::move(that.m_attributes)),
+      m_uniforms(std::move(that.m_uniforms))
+{
+    that.m_programID = 0;
+}
+
+Shader& Shader::operator=(Shader &&that)
+{
+    this->~Shader();
+
+    m_programID = that.m_programID;
+    m_attributes = std::move(that.m_attributes);
+    m_uniforms = std::move(that.m_uniforms);
+
+    that.m_programID = 0;
+
+    return *this;
+}
+
+// ================== Regular Use
+
+void Shader::bind()   const { glUseProgram(m_programID); }
+
+void Shader::unbind() const { glUseProgram(0); }
+
+GLuint Shader::getUniformLocation(std::string name)
+{
+    return glGetUniformLocation(m_programID, name.c_str());
+}
+
+GLuint Shader::getEnumeratedUniformLocation(std::string name, int index)
+{
+    std::string n = name + "[" + std::to_string(index) + "]";
+    return glGetUniformLocation(m_programID, n.c_str());
+}
+
+// ================== Setting Uniforms
+
+// Note: the overload to set matrix uniforms is in the .h file
+
+void Shader::setUniform(const std::string &name, float f)
+{
+    glUniform1f(m_uniforms[name], f);
+}
+
+void Shader::setUniform(const std::string &name, int i)
+{
+    glUniform1i(m_uniforms[name], i);
+}
+
+void Shader::setUniform(const std::string &name, bool b)
+{
+    glUniform1i(m_uniforms[name], static_cast<GLint>(b));
+}
+
+// ================== Creating the Program
+
+void Shader::createProgramID()
+{
+    m_programID = glCreateProgram();
+}
+
+void Shader::buildShaderProgramFromShaders(const std::vector<GLuint> &shaderHandles)
+{
+    // Attach shaders
+    for (const GLuint &shaderHandle : shaderHandles) {
+        glAttachShader(m_programID, shaderHandle);
+    }
+
+    // Link program
+    glLinkProgram(m_programID);
+    checkShaderLinkStatus(m_programID);
+
+    // Detach and delete shaders
+    for (const GLuint &shaderHandle : shaderHandles) {
+        glDetachShader(m_programID, shaderHandle);
+        glDeleteShader(shaderHandle);
+    }
+}
+
+// ================== Creating Shaders From Filepaths
+
+std::string Shader::getFileContents(std::string filepath)
+{
+    QString filepathStr = QString::fromStdString(filepath);
+    QFile file(filepathStr);
+
+    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        throw std::runtime_error(std::string("Failed to open shader: ") + filepath);
+    }
+
+    QTextStream stream(&file);
+    QString contents = stream.readAll();
+    file.close();
+
+    return contents.toStdString();
+}
+
+GLuint Shader::createShaderFromString(const std::string &str, GLenum shaderType)
+{
+    GLuint shaderHandle = glCreateShader(shaderType);
+
+    // Compile shader code
+    const char *codePtr = str.c_str();
+    glShaderSource(shaderHandle, 1, &codePtr, nullptr); // Assumes code is null terminated
+    glCompileShader(shaderHandle);
+
+    checkShaderCompilationStatus(shaderHandle);
+
+    return shaderHandle;
+}
+
+// ================== Discovering Attributes/Uniforms/Textures
+
+void Shader::discoverShaderData() {
+    discoverAttributes();
+    discoverUniforms();
+}
+
+void Shader::discoverAttributes() {
+    bind();
+    GLint attribCount;
+    glGetProgramiv(m_programID, GL_ACTIVE_ATTRIBUTES, &attribCount);
+    for (int i = 0; i < attribCount; i++) {
+        const GLsizei bufSize = 256;
+        GLsizei nameLength = 0;
+        GLint arraySize = 0;
+        GLenum type;
+        GLchar name[bufSize];
+        glGetActiveAttrib(m_programID, i, bufSize, &nameLength, &arraySize, &type, name);
+        name[std::min(nameLength, bufSize - 1)] = 0;
+        m_attributes[std::string(name)] = glGetAttribLocation(m_programID, name);
+    }
+    unbind();
+}
+
+void Shader::discoverUniforms() {
+    bind();
+    GLint uniformCount;
+    glGetProgramiv(m_programID, GL_ACTIVE_UNIFORMS, &uniformCount);
+    for (int i = 0; i < uniformCount; i++) {
+        const GLsizei bufSize = 256;
+        GLsizei nameLength = 0;
+        GLint arraySize = 0;
+        GLenum type;
+        GLchar name[bufSize];
+        glGetActiveUniform(m_programID, i, bufSize, &nameLength, &arraySize, &type, name);
+        name[std::min(nameLength, bufSize - 1)] = 0;
+
+        std::string strname(name);
+        if (isUniformArray(name, nameLength)) {
+            addUniformArray(strname, arraySize);
+        } else if (isTexture(type)) {
+            addTexture(strname);
+        } else {
+            addUniform(strname);
+        }
+    }
+    unbind();
+}
+
+bool Shader::isUniformArray(const GLchar *name, GLsizei nameLength) {
+    // Check if the last 3 characters are '[0]'
+    return (name[nameLength - 3] == '[') &&
+            (name[nameLength - 2] == '0') &&
+            (name[nameLength - 1] == ']');
+}
+
+bool Shader::isTexture(GLenum type) {
+    return (type == GL_SAMPLER_2D) ||
+            (type == GL_SAMPLER_CUBE);
+}
+
+void Shader::addUniformArray(const std::string &name, size_t size) {
+    std::string cleanName = name.substr(0, name.length() - 3);
+    for (auto i = static_cast<size_t>(0); i < size; i++) {
+        std::string enumeratedName = name;
+        enumeratedName[enumeratedName.length() - 2] = static_cast<char>('0' + i);
+        std::tuple< std::string, size_t > nameIndexTuple = std::make_tuple(cleanName, i);
+        m_uniformArrays[nameIndexTuple] = glGetUniformLocation(m_programID, enumeratedName.c_str());
+    }
+
+#if GRAPHICS_DEBUG_LEVEL > 0
+    m_trackedUniformArrays[name] = false;
+#endif
+}
+
+void Shader::addTexture(const std::string &name) {
+    GLint location = glGetUniformLocation(m_programID, name.c_str());
+    m_textureLocations[name] = location;
+    GLint slot = m_textureSlots.size();
+    m_textureSlots[location] = slot; // Assign slots in increasing order.
+
+#if GRAPHICS_DEBUG_LEVEL > 0
+    m_trackedTextures[name] = false;
+#endif
+}
+
+void Shader::addUniform(const std::string &name) {
+    m_uniforms[name] = glGetUniformLocation(m_programID, name.c_str());
+
+#if GRAPHICS_DEBUG_LEVEL > 0
+    m_trackedUniforms[name] = false;
+#endif
+}