From 66e8240ff7019b98fa15756da0b78e94bd5ebe47 Mon Sep 17 00:00:00 2001
From: Dominic Masters <dominic@domsplace.com>
Date: Tue, 9 Nov 2021 09:25:15 -0800
Subject: [PATCH] Working on shader code.

---
 src/display/shader.c | 36 +++++++++++++++++++++++++++++-------
 src/display/shader.h | 17 +++++++++++++++++
 2 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/src/display/shader.c b/src/display/shader.c
index 24b65779..b5e66fed 100644
--- a/src/display/shader.c
+++ b/src/display/shader.c
@@ -10,9 +10,12 @@
 void shaderInit(shader_t *shader,
   char *vertexShaderSource, char* fragmentShaderSource
 ) {
-  int isSuccess, maxLength;
+  int32_t isSuccess, maxLength, i;
   char *error;
   GLuint shaderVertex, shaderFragment, shaderProgram;
+  GLint size; // size of the variable
+  GLenum type; // type of the variable (float, vec3 or mat4, etc)
+  GLsizei length; // name length
 
   GLchar const* filesVertex[] = { vertexShaderSource };
   GLchar const* filesFragment[] = { fragmentShaderSource };
@@ -66,17 +69,28 @@ void shaderInit(shader_t *shader,
     glDeleteShader(shaderFragment);
     return;
   }
-
   // Everything is okay, let's create the encapsulated shader.
   shader->shaderVertex = shaderVertex;
   shader->shaderFrag = shaderFragment;
   shader->shaderProgram = shaderProgram;
 
-  shader->uniProj = glGetUniformLocation(shader->shaderProgram,SHADER_UNI_PROJ);
-  shader->uniView = glGetUniformLocation(shader->shaderProgram,SHADER_UNI_VIEW);
-  shader->uniText = glGetUniformLocation(shader->shaderProgram,SHADER_UNI_TEXT);
-  shader->uniModl = glGetUniformLocation(shader->shaderProgram,SHADER_UNI_MODL);
-  shader->uniColr = glGetUniformLocation(shader->shaderProgram,SHADER_UNI_COLR);
+  // Extract uniforms
+  glGetProgramiv(shaderProgram, GL_ACTIVE_UNIFORMS, &shader->uniformCount);
+
+  for(i = 0; i < shader->uniformCount; i++) {
+    shader->uniforms[i] = shader->uniformBuffer + (i * SHADER_UNIFORM_NAME_MAX);
+    glGetActiveUniform(
+      shaderProgram, (GLuint)i, SHADER_UNIFORM_NAME_MAX,
+      &length, &size, &type, shader->uniforms[i]
+    );
+  }
+  
+  // Hold off on this for now
+  shader->uniProj = shaderGetUniform(shader, SHADER_UNI_PROJ);
+  shader->uniView = shaderGetUniform(shader, SHADER_UNI_VIEW);
+  shader->uniText = shaderGetUniform(shader, SHADER_UNI_TEXT);
+  shader->uniModl = shaderGetUniform(shader, SHADER_UNI_MODL);
+  shader->uniColr = shaderGetUniform(shader, SHADER_UNI_COLR);
 
   // Bind the shader
   shaderUse(shader);
@@ -86,6 +100,14 @@ void shaderInit(shader_t *shader,
   shaderUseColor(shader, PIXEL_COLOR_WHITE);
 }
 
+shaderuniform_t shaderGetUniform(shader_t *shader, char *name) {
+  int32_t i;
+  for(i = 0; i < shader->uniformCount; i++) {
+    if(strcmp(shader->uniforms[i], name) == 0) return i;
+  }
+  return (shaderuniform_t)-1;
+}
+
 void shaderDispose(shader_t *shader) {
   glDeleteProgram(shader->shaderProgram);
   glDeleteShader(shader->shaderVertex);
diff --git a/src/display/shader.h b/src/display/shader.h
index 96d1ff56..e1f68e60 100644
--- a/src/display/shader.h
+++ b/src/display/shader.h
@@ -10,6 +10,7 @@
 #include "matrix.h"
 #include "camera.h"
 #include "texture.h"
+#include "../util/array.h"
 
 #define SHADER_UNI_VIEW "u_View"
 #define SHADER_UNI_PROJ "u_Proj"
@@ -17,6 +18,9 @@
 #define SHADER_UNI_MODL "u_Modl"
 #define SHADER_UNI_COLR "u_Colr"
 
+#define SHADER_UNIFORM_NAME_MAX 24
+#define SHADER_UNIFORM_COUNT 8
+
 /** Representation of a shader uniform */
 typedef GLuint shaderuniform_t;
 
@@ -48,6 +52,10 @@ typedef struct {
 
   /** Uniform for the color multiplier */
   shaderuniform_t uniColr;
+
+  char uniformBuffer[SHADER_UNIFORM_NAME_MAX * SHADER_UNIFORM_COUNT];
+  char *uniforms[SHADER_UNIFORM_COUNT];
+  int32_t uniformCount;
 } shader_t;
 
 /**
@@ -60,6 +68,15 @@ void shaderInit(shader_t *shader,
   char *vertexShaderSource, char* fragmentShaderSource
 );
 
+/**
+ * Return the shaderuniform_t for a given shader uniform name.
+ * 
+ * @param shader Shader to get from
+ * @param name Name to look for
+ * @return The shader uniform, or -1 if not found.
+ */
+shaderuniform_t shaderGetUniform(shader_t *shader, char *name);
+
 /**
  * Cleanup and unload a previously loaded shader.
  * @param shader The shader to unload