From 39cc17db686b9e02394510442ed388b4097d6bdb Mon Sep 17 00:00:00 2001
From: cinnaboot <cinnaboot@protonmail.com>
Date: Thu, 10 Feb 2022 18:28:01 -0500
Subject: [PATCH] remove fixed properties of ShaderProgram in favor of dynamic
 properties

this makes use of our dynamic shader parsing code, so we don't need to
track these properties explicitly any more.
---
 src/shader.cpp  | 47 ++++++++++++++++++++++++++++++++++++++---------
 src/shader.h    | 20 ++++++++++++++++----
 src/tangerine.h |  1 +
 3 files changed, 55 insertions(+), 13 deletions(-)

diff --git a/src/shader.cpp b/src/shader.cpp
index 32b1e3f..242d928 100644
--- a/src/shader.cpp
+++ b/src/shader.cpp
@@ -102,9 +102,6 @@ addShaderProgram(MemoryArena* arena,
 		GLuint vs_id, fs_id;
 
 		if (compileAndLinkShader(s, v_str, f_str, vs_id, fs_id)) {
-			s->node_xform_id = glGetUniformLocation(s->prog_id, "node_xform");
-			// TODO: add sampler uniform detection in dynamic shader parsing
-			s->sampler_id = glGetUniformLocation(s->prog_id, "sampler");
 			glDetachShader(s->prog_id, vs_id);
 			glDetachShader(s->prog_id, fs_id);
 			glDeleteShader(vs_id);
@@ -239,12 +236,21 @@ renderVAO(GLMesh* glmesh,
 {
 	glUseProgram(shader->prog_id);
 	glBindVertexArray(glmesh->vao_id);
-	glUniformMatrix4fv(shader->node_xform_id, 1, GL_FALSE,
-		(float*) node_xform);
 
-	if (glmesh->has_texture) {
-		glBindTexture(GL_TEXTURE_2D, gl_tex->id);
-		glUniform1i(shader->sampler_id, 0);
+	for (u32 i = 0; i < shader->num_uniforms; i++) {
+		const GLUniform& uniform = shader->uniforms[i];
+
+		if (uniform.uniform_type == UNIFORM_NODE_XFORM) {
+			glUniformMatrix4fv(uniform.location, 1, GL_FALSE,
+								(float*) node_xform);
+		}
+
+		else if (glmesh->has_texture &&
+				uniform.uniform_type == UNIFORM_SAMPLER)
+		{
+			glBindTexture(GL_TEXTURE_2D, gl_tex->id);
+			glUniform1i(uniform.location, 0);
+		}
 	}
 
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, glmesh->element_buf->id);
@@ -519,6 +525,27 @@ getGLTypeSizeStd140(GLenum e)
 	}
 }
 
+UniformType
+getUniformType(const char* name)
+{
+	if (utilCStrMatch(name, "sampler"))
+		return UNIFORM_SAMPLER;
+	else if (utilCStrMatch(name, "node_xform"))
+		return UNIFORM_NODE_XFORM;
+	else if (utilCStrMatch(name, "normal_xform"))
+		return UNIFORM_NORMAL_XFORM;
+	else if (utilCStrMatch(name, "view_xform"))
+		return UNIFORM_VIEW_XFORM;
+	else if (utilCStrMatch(name, "proj_xform"))
+		return UNIFORM_PROJECTION_XFORM;
+	else if (utilCStrMatch(name, "matrices"))
+		return UNIFORM_BLOCK_XFORMS;
+	else if (utilCStrMatch(name, "lights"))
+		return UNIFORM_BLOCK_LIGHTS;
+	else
+		return UNIFORM_UNKNOWN;
+}
+
 const GLUniform
 parseUniform(MemoryArena* arena, ShaderProgram* s, u32 uniform_idx)
 {
@@ -532,7 +559,7 @@ parseUniform(MemoryArena* arena, ShaderProgram* s, u32 uniform_idx)
 		sizeof(unif_name),
 		&name_len,
 		&unif.num_elements,
-		&unif.uniform_type,
+		&unif.gl_type,
 		unif_name);
 
 	glGetActiveUniformsiv(s->prog_id, 1, &uniform_idx, GL_UNIFORM_BLOCK_INDEX,
@@ -543,6 +570,7 @@ parseUniform(MemoryArena* arena, ShaderProgram* s, u32 uniform_idx)
 							&unif.uniform_offset);
 
 	unif.name = arenaCopyCStr(arena, unif_name);
+	unif.uniform_type = getUniformType(unif.name);
 	unif.location = glGetUniformLocation(s->prog_id, unif.name);
 
 	return unif;
@@ -635,6 +663,7 @@ parseUniformBlocks(MemoryArena* arena, ShaderProgram* s, GLContext* gl_ctx)
 		glGetActiveUniformBlockName(
 				s->prog_id, i, 256, &name_len, block_name);
 		ub.name = arenaCopyCStr(arena, block_name);
+		ub.uniform_type = getUniformType(ub.name);
 
 		glGetActiveUniformBlockiv(s->prog_id, i,
 				GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS, (GLint*) &ub.num_uniforms);
diff --git a/src/shader.h b/src/shader.h
index 8978003..0561a67 100644
--- a/src/shader.h
+++ b/src/shader.h
@@ -9,6 +9,19 @@
 #include "util.h"
 
 
+enum UniformType
+{
+	UNIFORM_SAMPLER,
+	UNIFORM_NODE_XFORM,
+	UNIFORM_VIEW_XFORM,
+	UNIFORM_PROJECTION_XFORM,
+	UNIFORM_NORMAL_XFORM,
+	UNIFORM_BLOCK_XFORMS,
+	UNIFORM_BLOCK_LIGHTS,
+	UNIFORM_UNKNOWN,
+	UNIFORM_TYPE_COUNT
+};
+
 struct GLUniform
 {
 	// NOTE: would be nice to use idx as the location parameter because it seems
@@ -17,7 +30,8 @@ struct GLUniform
 	GLuint idx;
 	GLint location;
 	GLint block_idx;
-	GLenum uniform_type; // NOTE: GL_UNSIGNED_INT, GL_FLOAT_VEC4
+	UniformType uniform_type;
+	GLenum gl_type; // NOTE: GL_UNSIGNED_INT, GL_FLOAT_VEC4
 	GLint num_elements; // NOTE: 1 unless uniform is an array of base types
 	GLint array_stride; // NOTE: bytes between array elements
 	GLint uniform_offset; // NOTE: byte offset from beginning of uniform
@@ -28,6 +42,7 @@ struct GLUniformBlock
 {
 	GLuint block_id;
 	GLint binding_idx;
+	UniformType uniform_type;
 	GLuint num_uniforms;
 	GLUniform* uniforms;
 	char* name;
@@ -65,9 +80,6 @@ struct GLBufferToAttribMapping
 struct ShaderProgram
 {
 	GLuint prog_id;
-	GLuint xforms_ubo_id;
-	GLuint node_xform_id;
-	GLint sampler_id;
 
 	u32 num_blocks;
 	GLUniformBlock* uniform_blocks;
diff --git a/src/tangerine.h b/src/tangerine.h
index b52e052..f20f136 100644
--- a/src/tangerine.h
+++ b/src/tangerine.h
@@ -58,6 +58,7 @@
 *  		- need a separate GLBufferToAttribMapping for each mesh on an entity
 *  		- maybe fixed now with MeshBufferType enum and getMeshData()
 *  - allow entities to have an empty diffuse texture (see initEntity())
+*  - use dynamic shader parsing to set 'sampler_id' for shaders with textures
 */