From fb23c8d47f6dcef429423256d8dddcc0f7184fc4 Mon Sep 17 00:00:00 2001
From: Samuel Fadel <samuel@nihil.ws>
Date: Sun, 4 Jun 2023 13:02:14 +0200
Subject: Further advances in nuklear port.

Rendering now looks similar to Qt version, needs a few tweaks:
* Proper multisampling
* Background

Missing features:
* Barcharts
* Interactivity (e.g. brushing/linking in all objects)
* History view of interactions
---
 shader.cpp | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
 create mode 100644 shader.cpp

(limited to 'shader.cpp')

diff --git a/shader.cpp b/shader.cpp
new file mode 100644
index 0000000..0a1268e
--- /dev/null
+++ b/shader.cpp
@@ -0,0 +1,137 @@
+#include "shader.h"
+
+#include <iostream>
+
+static int setupShader(GLenum shaderType, const char *src)
+{
+    GLuint shader = glCreateShader(shaderType);
+    glShaderSource(shader, 1, &src, nullptr);
+    glCompileShader(shader);
+
+    int status;
+    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+    if (status == GL_FALSE) {
+        char buf[1024];
+        glGetShaderInfoLog(shader, sizeof buf, nullptr, buf);
+        std::cerr << "Error: "
+                  << (shaderType == GL_VERTEX_SHADER ? "vertex" : "fragment")
+                  << " shader: compilation failed: "
+                  << buf
+                  << std::endl;
+    }
+    return shader;
+}
+
+Shader::Shader(const char *vertexSrc, const char *fragmentSrc, const char *geometrySrc)
+{
+    GLuint vertex = setupShader(GL_VERTEX_SHADER, vertexSrc);
+    GLuint fragment = setupShader(GL_FRAGMENT_SHADER, fragmentSrc);
+    GLuint geometry;
+    if (geometrySrc != nullptr) {
+        geometry = setupShader(GL_GEOMETRY_SHADER, geometrySrc);
+    }
+
+    int status;
+    m_program = glCreateProgram();
+    glAttachShader(m_program, vertex);
+    glAttachShader(m_program, fragment);
+    if (geometrySrc != nullptr) {
+        glAttachShader(m_program, geometry);
+    }
+    glLinkProgram(m_program);
+    glGetProgramiv(m_program, GL_LINK_STATUS, &status);
+    if (status == GL_FALSE) {
+        char buf[1024];
+        glGetProgramInfoLog(m_program, sizeof buf, nullptr, buf);
+        std::cerr << "Error: shader linking failed: "
+                  << buf
+                  << std::endl;
+    }
+
+    if (geometrySrc != nullptr) {
+        glDeleteShader(geometry);
+    }
+    glDeleteShader(fragment);
+    glDeleteShader(vertex);
+}
+
+Shader::~Shader()
+{
+    glDeleteProgram(m_program);
+}
+
+void Shader::use() const
+{
+    glUseProgram(m_program);
+}
+
+void Shader::release() const
+{
+    glUseProgram(0);
+}
+
+GLint Shader::uniformLocation(const char *name) const
+{
+    return glGetUniformLocation(m_program, name);
+}
+
+void Shader::setUniform(GLint location, GLint value) const
+{
+    glUniform1i(location, value);
+}
+
+void Shader::setUniform(GLint location, GLfloat value) const
+{
+    glUniform1f(location, value);
+}
+
+void Shader::setUniform(GLint location, GLfloat mat[4][4]) const
+{
+    // GL_FALSE for column-major
+    glUniformMatrix4fv(location, 1, GL_FALSE, &mat[0][0]);
+}
+
+void Shader::setUniform1dArray(GLint location, const GLfloat *values, int count) const
+{
+    glUniform1fv(location, count, values);
+}
+
+void Shader::setUniform2dArray(GLint location, const GLfloat *values, int count) const
+{
+    glUniform2fv(location, count, values);
+}
+
+void Shader::setUniform3dArray(GLint location, const GLfloat *values, int count) const
+{
+    glUniform3fv(location, count, values);
+}
+
+void Shader::setUniform(const char *name, GLint value) const
+{
+    setUniform(uniformLocation(name), value);
+}
+
+void Shader::setUniform(const char *name, GLfloat value) const
+{
+    setUniform(uniformLocation(name), value);
+}
+
+void Shader::setUniform1dArray(const char *name, const GLfloat *values, int count) const
+{
+    setUniform1dArray(uniformLocation(name), values, count);
+}
+
+void Shader::setUniform2dArray(const char *name, const GLfloat *values, int count) const
+{
+    setUniform2dArray(uniformLocation(name), values, count);
+}
+
+void Shader::setUniform3dArray(const char *name, const GLfloat *values, int count) const
+{
+    setUniform3dArray(uniformLocation(name), values, count);
+}
+
+void Shader::setUniform(const char *name, GLfloat mat[4][4]) const
+{
+    setUniform(uniformLocation(name), mat);
+}
-- 
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