From bd57f345ed9dbed1d81683e48199626de2ea9044 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Fri, 27 Jun 2025 10:18:39 -0700
Subject: Restructure project

---
 src/core/shader.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 src/core/shader.c

(limited to 'src/core/shader.c')

diff --git a/src/core/shader.c b/src/core/shader.c
new file mode 100644
index 0000000..dded084
--- /dev/null
+++ b/src/core/shader.c
@@ -0,0 +1,92 @@
+#include "shader.h"
+
+#include "gl_util.h"
+#include <gfx_assert.h>
+
+#include <cstring.h>
+#include <log/log.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+static GLenum shader_type_to_gl(ShaderType type) {
+  switch (type) {
+  case VertexShader:
+    return GL_VERTEX_SHADER;
+  case FragmentShader:
+    return GL_FRAGMENT_SHADER;
+  }
+  FAIL("shader_type_to_gl(): missing case");
+  return GL_INVALID_ENUM;
+}
+
+static lstring make_defines_string(const ShaderDesc* desc) {
+  lstring defines = {0};
+  for (size_t i = 0; i < desc->num_defines; ++i) {
+    const ShaderCompilerDefine* define = &desc->defines[i];
+    lstring_append_cstr(&defines, "#define ");
+    lstring_append_cstr(&defines, sstring_cstr(&define->name));
+    lstring_append_cstr(&defines, " ");
+    lstring_append_cstr(&defines, sstring_cstr(&define->value));
+    lstring_append_cstr(&defines, "\n");
+  }
+  return defines;
+}
+
+/// Creates an OpenGL shader.
+/// Returns non-zero on success, 0 on failure.
+static GLuint create_shader(const ShaderDesc* desc) {
+  const GLuint shader = glCreateShader(shader_type_to_gl(desc->type));
+  if (!shader) {
+    return 0;
+  }
+
+#if GFX_GL_CONTEXT == GFX_GL_CONTEXT_ES
+  const char* header = "#version 300 es\n\nprecision highp float;";
+#else
+  const char* header = "#version 400 core\n\n";
+#endif
+
+  lstring defines = make_defines_string(desc);
+
+  const char* source_bits[]    = {header, lstring_cstr(&defines), desc->code};
+  const GLint source_lengths[] = {
+      strlen(header), lstring_length(&defines), strlen(desc->code)};
+
+  glShaderSource(shader, 3, source_bits, source_lengths);
+  glCompileShader(shader);
+  GLint result;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &result);
+  if (result == GL_FALSE) {
+    GLint log_len;
+    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_len);
+    if (log_len > 0) {
+      char* log = calloc(log_len, sizeof(char));
+      glGetShaderInfoLog(shader, log_len, NULL, log);
+      static const char* sep = "----------";
+      LOGE("Failed loading shader: %s\n%s\n%s\n%s", log, sep, desc->code, sep);
+      free(log);
+    } else {
+      LOGE("Failed loading shader:\n%s", desc->code);
+    }
+    glDeleteShader(shader);
+    return 0;
+  }
+  ASSERT_GL;
+  return shader;
+}
+
+bool gfx_compile_shader(Shader* shader, const ShaderDesc* desc) {
+  shader->id = create_shader(desc);
+  return shader->id != 0;
+}
+
+void gfx_del_shader(Shader* shader) {
+  assert(shader);
+
+  if (shader->id) {
+    glDeleteShader(shader->id);
+    shader->id = 0;
+  }
+  ASSERT_GL;
+}
-- 
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