From 10e4ea0f28803dbea4b74319f7bb917d1acf560c Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Tue, 24 Jul 2018 16:30:25 -0700
Subject: [core] Compress all shader source as a single corpus

---
 scripts/generate-shaders.js | 82 +++++++++++++++++++++++++++++++++------------
 1 file changed, 60 insertions(+), 22 deletions(-)

(limited to 'scripts/generate-shaders.js')

diff --git a/scripts/generate-shaders.js b/scripts/generate-shaders.js
index 39307f358a..5532bd33cd 100755
--- a/scripts/generate-shaders.js
+++ b/scripts/generate-shaders.js
@@ -12,24 +12,66 @@ delete shaders.lineGradient;
 
 require('./style-code');
 
-function compressedData(src) {
-    return zlib.deflateSync(src, {level: zlib.Z_BEST_COMPRESSION})
-        .toString('hex')
-        .match(/.{1,16}/g)
-        .map(line => line.match(/.{1,2}/g).map(n => `0x${n}`).join(', '))
-        .join(',\n        ')
-        .trim();
+let concatenated = '';
+let offsets = {};
+
+for (const key in shaders) {
+    const vertex = concatenated.length;
+    concatenated += shaders[key].vertexSource;
+    concatenated += '\0';
+
+    const fragment = concatenated.length;
+    concatenated += shaders[key].fragmentSource;
+    concatenated += '\0';
+
+    offsets[key] = {vertex, fragment};
+}
+
+const compressed = zlib.deflateSync(concatenated, {level: zlib.Z_BEST_COMPRESSION})
+    .toString('hex')
+    .match(/.{1,16}/g)
+    .map(line => line.match(/.{1,2}/g).map(n => `0x${n}`).join(', '))
+    .join(',\n        ')
+    .trim();
+
+function sourceOffset(key, type) {
+    return `source() + ${offsets[key][type]}`
 }
 
-function compressedConstant(data) {
-    return `[] () {
+writeIfModified(path.join(outputPath, 'source.hpp'), `// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
+
+#pragma once
+
+namespace mbgl {
+namespace shaders {
+
+const char* source();
+
+} // namespace shaders
+} // namespace mbgl
+`);
+
+writeIfModified(path.join(outputPath, 'source.cpp'), `// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
+
+#include <mbgl/shaders/source.hpp>
+#include <mbgl/util/compression.hpp>
+
+#include <cstdint>
+
+namespace mbgl {
+namespace shaders {
+
+const char* source() {
     static const uint8_t compressed[] = {
-        ${compressedData(data)}
+        ${compressed}
     };
     static std::string decompressed = util::decompress(std::string(reinterpret_cast<const char*>(compressed), sizeof(compressed)));
     return decompressed.c_str();
-}()`
-}
+};
+
+} // namespace shaders
+} // namespace mbgl
+`);
 
 writeIfModified(path.join(outputPath, 'preludes.hpp'), `// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
 
@@ -48,15 +90,13 @@ extern const char* fragmentPrelude;
 writeIfModified(path.join(outputPath, 'preludes.cpp'), `// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
 
 #include <mbgl/shaders/preludes.hpp>
-#include <mbgl/util/compression.hpp>
-
-#include <cstdint>
+#include <mbgl/shaders/source.hpp>
 
 namespace mbgl {
 namespace shaders {
 
-const char* vertexPrelude = ${compressedConstant(shaders.prelude.vertexSource)};
-const char* fragmentPrelude = ${compressedConstant(shaders.prelude.fragmentSource)};
+const char* vertexPrelude = ${sourceOffset('prelude', 'vertex')};
+const char* fragmentPrelude = ${sourceOffset('prelude', 'fragment')};
 
 } // namespace shaders
 } // namespace mbgl
@@ -89,16 +129,14 @@ public:
     writeIfModified(path.join(outputPath, `${shaderName}.cpp`), `// NOTE: DO NOT CHANGE THIS FILE. IT IS AUTOMATICALLY GENERATED.
 
 #include <mbgl/shaders/${shaderName}.hpp>
-#include <mbgl/util/compression.hpp>
-
-#include <cstdint>
+#include <mbgl/shaders/source.hpp>
 
 namespace mbgl {
 namespace shaders {
 
 const char* ${shaderName}::name = "${shaderName}";
-const char* ${shaderName}::vertexSource = ${compressedConstant(shaders[key].vertexSource)};
-const char* ${shaderName}::fragmentSource = ${compressedConstant(shaders[key].fragmentSource)};
+const char* ${shaderName}::vertexSource = ${sourceOffset(key, 'vertex')};
+const char* ${shaderName}::fragmentSource = ${sourceOffset(key, 'fragment')};
 
 } // namespace shaders
 } // namespace mbgl
-- 
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