From b23bfbdcd8f9fd2492666f2ab4936121cd7a8a81 Mon Sep 17 00:00:00 2001
From: Kienan Stewart <kienan.stewart@burntworld.ca>
Date: Wed, 12 Feb 2020 21:30:38 -0500
Subject: [PATCH] Use the default shader program for the triangle render

---
 src/client/client_imgui.cpp |  4 ++++
 src/common/shaderloader.hpp | 27 +++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/client/client_imgui.cpp b/src/client/client_imgui.cpp
index 834dc0c..e399384 100644
--- a/src/client/client_imgui.cpp
+++ b/src/client/client_imgui.cpp
@@ -129,6 +129,9 @@ int main(int argc, char** argv)
        // Render game geometries
        // @see https://blog.conan.io/2019/06/26/An-introduction-to-the-Dear-ImGui-library.html
        // 1st attribute buffer : vertices
+       GLuint p = find_shader_program_by_name("default", &shader_program_registry);
+       printf("Using program %d\n", p);
+       glUseProgram(p);
        glEnableVertexAttribArray(0);
        glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
        glVertexAttribPointer(
@@ -142,6 +145,7 @@ int main(int argc, char** argv)
        // Draw the triangle !
        glDrawArrays(GL_TRIANGLES, 0, 3); // Starting from vertex 0; 3 vertices total -> 1 triangle
        glDisableVertexAttribArray(0);
+       glUseProgram(0);
 
        // Start the Dear ImGui frame
        ImGui_ImplOpenGL3_NewFrame();
diff --git a/src/common/shaderloader.hpp b/src/common/shaderloader.hpp
index 9ee2393..77b5cca 100644
--- a/src/common/shaderloader.hpp
+++ b/src/common/shaderloader.hpp
@@ -34,7 +34,7 @@ class RegisteredShaderProgram {
 public:
    RegisteredShaderProgram(char *name, GLuint programID) {
       int name_size = strlen(name);
-      char *n = (char*) calloc(name_size, sizeof(char));
+      char *n = (char*) calloc(name_size + 1, sizeof(char));
       strncpy(n, name, name_size);
       this->programName = n;
       this->programID = programID;
@@ -42,8 +42,30 @@ public:
    ~RegisteredShaderProgram() {
       free(this->programName);
    }
+   char* get_program_name() {
+      return this->programName;
+   }
+   GLuint get_program_id() {
+      return this->programID;
+   }
 };
 
+GLuint find_shader_program_by_name(const char *name, std::vector<RegisteredShaderProgram> *r) {
+   GLuint programID = 0;
+   for(auto i = r->begin() ; i != r->end() ; ++i) {
+      if (strlen(name) != strlen(i->get_program_name())) {
+         // String lengths aren't the same, so carry on.
+         continue;
+      }
+      if(strncmp(i->get_program_name(), name, strlen(name)) == 0) {
+         programID = i->get_program_id();
+      } else {
+         continue;
+      }
+   }
+   return programID;
+}
+
 struct ShaderRegistry {
    struct RegisteredShader *list = 0;
    int size = 0;
@@ -241,7 +263,8 @@ int loadShaderProgramsFromFile(const char* file_path, struct ShaderRegistry *sha
 
       // Add to program_registry
       if (InfoLogLength == 0) {
-         program_registry->push_back(RegisteredShaderProgram(name, program));
+         auto p = new RegisteredShaderProgram(name, program);
+         program_registry->push_back(*p);
       }
       free(program_list_copy);
       free(line_copy);