From 4a1880e22a8f720852cfbfffed34801591c99824 Mon Sep 17 00:00:00 2001
From: omigamedev <omarator@gmail.com>
Date: Tue, 8 Jan 2019 11:02:07 +0100
Subject: [PATCH] implement framebuffer fetch on iOS for bleding

---
 src/app_shaders.cpp | 12 +++++++++++-
 src/node_canvas.cpp | 11 +++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/app_shaders.cpp b/src/app_shaders.cpp
index 0cd47e1..7172cab 100644
--- a/src/app_shaders.cpp
+++ b/src/app_shaders.cpp
@@ -85,16 +85,27 @@ void App::initShaders()
         "}\n";
     static const char* shader_blend_f =
         SHADER_VERSION
+#ifdef __IOS__
+        "#extension GL_EXT_shader_framebuffer_fetch : enable\n"
+#endif
         "uniform sampler2D tex;\n"
         "uniform sampler2D tex_alpha;\n"
         "uniform sampler2D tex_bg;\n"
         "uniform mediump float alpha;\n"
         "uniform int blend_mode;\n"
         "in mediump vec2 uv;\n"
+#ifdef __IOS__
+        "inout mediump vec4 frag;\n"
+#else
         "out mediump vec4 frag;\n"
+#endif
         SHADER_FUNCTION_BLEND
         "void main() {\n"
+#ifdef __IOS__
+        "   mediump vec4 bg = frag;\n"
+#else
         "   mediump vec4 bg = texture(tex_bg, uv);\n"
+#endif
         "   mediump vec4 fg = vec4(texture(tex, uv).rgb, texture(tex_alpha, uv).a);\n"
         "   if (fg.a == 0.0) { frag = bg; return; }\n"
         "   mediump float contribution = (1.0 - bg.a) * fg.a;\n"
@@ -338,7 +349,6 @@ void App::initShaders()
         SHADER_VERSION
 #ifdef __IOS__
         "#extension GL_EXT_shader_framebuffer_fetch : enable\n"
-//        "#extension GL_EXT_shader_image_load_store : enable\n"
 #endif
         "uniform mediump sampler2D tex;\n"
         "uniform mediump sampler2D tex_bg;\n"
diff --git a/src/node_canvas.cpp b/src/node_canvas.cpp
index 606b6e6..edd8fe7 100644
--- a/src/node_canvas.cpp
+++ b/src/node_canvas.cpp
@@ -271,7 +271,9 @@ void NodeCanvas::draw()
                 ShaderManager::use(kShader::TextureBlend);
                 ShaderManager::u_int(kShaderUniform::Tex, 0);
                 ShaderManager::u_int(kShaderUniform::TexA, 1);
+#ifndef __IOS__
                 ShaderManager::u_int(kShaderUniform::TexBG, 2);
+#endif
                 ShaderManager::u_int(kShaderUniform::BlendMode, m_canvas->m_layers[layer_index].m_blend_mode);
                 ShaderManager::u_float(kShaderUniform::Alpha, 1.f);
                 ShaderManager::u_mat4(kShaderUniform::MVP, glm::ortho(-1, 1, -1, 1));
@@ -280,16 +282,21 @@ void NodeCanvas::draw()
                 m_blender_rtt.bindTexture();
                 glActiveTexture(GL_TEXTURE1);
                 m_blender_rtt.bindTexture();
+#ifndef __IOS__
                 glActiveTexture(GL_TEXTURE2);
                 m_blender_bg.bind();
-                glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, m_blender_bg.size().x, m_blender_bg.size().y);
+                glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, 
+                    m_blender_bg.size().x, m_blender_bg.size().y);
+#endif
 
                 m_face_plane.draw_fill();
 
+#ifndef __IOS__
                 glActiveTexture(GL_TEXTURE2);
                 m_blender_bg.unbind();
+#endif
                 glActiveTexture(GL_TEXTURE1);
-                m_blender_bg.unbind();
+                m_blender_rtt.unbindTexture();
                 glActiveTexture(GL_TEXTURE0);
                 m_blender_rtt.unbindTexture();