From e827fd28abfacee5784b5a86548ebd668c84a070 Mon Sep 17 00:00:00 2001
From: xo <boneyaard@gmail.com>
Date: Mon, 13 Apr 2026 01:46:46 +0200
Subject: fix drawing on intel gpus

---
 src/render/gl.cpp     | 34 ++++++++++++++++++++++++++++------
 src/render/gl.h       |  2 +-
 src/render/gl_batch.h |  2 +-
 src/util/string.h     |  7 +++++++
 4 files changed, 37 insertions(+), 8 deletions(-)

(limited to 'src')

diff --git a/src/render/gl.cpp b/src/render/gl.cpp
index 9aef44c..44d5079 100644
--- a/src/render/gl.cpp
+++ b/src/render/gl.cpp
@@ -289,13 +289,13 @@ STAT gl_shader_compile( GL_DATA* gl, GL_SHADER_DEF* shader ) {
 
   I32 res;
   shader->id = glCreateShader( (GLenum)shader->type );
-  glShaderSource( shader->id, 1, &shader->code, 0 );
+  glShaderSource( shader->id, 1, &shader->code.data, 0 );
   glCompileShader( shader->id );
   glGetShaderiv( shader->id, GL_COMPILE_STATUS, &res );
 
   if( !res ) {
     glGetShaderInfoLog( shader->id, 8192, 0, log_buf );
-    dlog( "gl_shader_compile() : error compiling shader %s. log: \n%s\n%s", shader->name, log_buf, shader->code );
+    dlog( "gl_shader_compile() : error compiling shader %s. log: \n%s\n%s", shader->name, log_buf, shader->code.data );
 
     glDeleteShader( shader->id );
     return STAT_ERR;
@@ -305,13 +305,11 @@ STAT gl_shader_compile( GL_DATA* gl, GL_SHADER_DEF* shader ) {
   return STAT_OK;
 }
 
-void gl_shader_destroy( GL_DATA* gl, GL_SHADER_DEF* shader ) {
-  if( shader->code )
-    free( (void*)shader->code );
-}
+void gl_shader_destroy( GL_DATA* gl, GL_SHADER_DEF* shader ) {}
 
 GL_SHADER_PROGRAM* gl_program_create( GL_DATA* gl, const char* name, U32 size ) {
   GL_SHADER_PROGRAM* program = (GL_SHADER_PROGRAM*)malloc( size );
+  memset( program, 0, size );
   char        shader_string[256];
   char*       shader_code;
 
@@ -344,11 +342,35 @@ GL_SHADER_PROGRAM* gl_program_create( GL_DATA* gl, const char* name, U32 size )
   return program;
 }
 
+void gl_program_insert_sample_gate( GL_DATA* gl, GL_SHADER_DEF* shader ) {
+  I32 sample_start = shader->code.idx_of( "extern batch_sample(" );
+  if( sample_start == -1 )
+    return;
+
+  I32 sample_end = shader->code.idx_of( ");", sample_start );
+  if( sample_end == -1 )
+    return;
+
+  STR start = shader->code.substr( 0, sample_start );
+  STR end = shader->code.substr( sample_end + 2 );
+
+  STR func  = "vec4 batch_sample( vec2 in_tex ) {\n";
+  func     += "  vec4 tex_color = vec4( 1.0, 1.0, 1.0, 1.0 );\n";
+  for( U32 i = 0; i < gl->shader_texture_limit; ++i )
+    func.fmt( "  if( g_sampler == %du ) tex_color = texture2D( g_samplers[%d], in_tex );\n", i, i );
+  func     += "  return tex_color;";
+  func     += "}\n";
+
+  shader->code = start + func + end;
+}
+
 STAT gl_program_compile( GL_DATA* gl, GL_SHADER_PROGRAM* program ) {
   static char* log_buf = 0;
   if( !log_buf )
     log_buf = (char*)malloc( 8192 );
 
+  gl_program_insert_sample_gate( gl, &program->fsh );
+
   program->id = glCreateProgram();
   if( !OK( gl_shader_compile( gl, &program->fsh ) )
    || !OK( gl_shader_compile( gl, &program->vsh ) ) )
diff --git a/src/render/gl.h b/src/render/gl.h
index b673d47..a95994d 100644
--- a/src/render/gl.h
+++ b/src/render/gl.h
@@ -20,7 +20,7 @@ struct VERTEX {
 
 struct GL_SHADER_DEF {
   const char* name;
-  const char* code;
+  STR         code;
   I32         type;
   U32         id;
   U8          compiled;
diff --git a/src/render/gl_batch.h b/src/render/gl_batch.h
index 31ed0ea..ed74d74 100644
--- a/src/render/gl_batch.h
+++ b/src/render/gl_batch.h
@@ -120,8 +120,8 @@ inline void gl_batch_draw( GL_BATCH<VERTEX>* batch ) {
       GL_DYNAMIC_DRAW
     );
 
-    glBindBuffer( GL_ARRAY_BUFFER, 0 );
     glDrawArrays( call->primitive, 0, call->vertices.size );
+    glBindBuffer( GL_ARRAY_BUFFER, 0 );
   } );
 
   gl_set_viewport( batch->gl, vp_start, vp_dim );
diff --git a/src/util/string.h b/src/util/string.h
index 2725fd2..548007a 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -277,6 +277,13 @@ struct __str : public LIST<CT> {
     return ret;
   }
 
+  __str<CT> substr( I32 start ) {
+    if( start < 0 )
+      start = this->size + start;
+
+    return __str<CT>( this->size - start, this->data + start );
+  }
+
   // can take negative input as offset from end
   __str<CT> substr( I32 start, I32 end ) {
     if( start < 0 )
-- 
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