From b7d6c5b664ff3701e6842e61c40b9ed31f74732a Mon Sep 17 00:00:00 2001
From: BZLZHH <admin@bzlzhh.top>
Date: Thu, 30 Jan 2025 19:53:55 +0800
Subject: [PATCH] [Feat] (shader.c): Process uniform variables declarations.

Signed-off-by: BZLZHH <admin@bzlzhh.top>
---
 src/main/cpp/gl/shader.c | 144 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)

diff --git a/src/main/cpp/gl/shader.c b/src/main/cpp/gl/shader.c
index 54b4e92..bcc2427 100644
--- a/src/main/cpp/gl/shader.c
+++ b/src/main/cpp/gl/shader.c
@@ -16,6 +16,149 @@
 
 #define DEBUG 0
 
+void trim(char* str) {
+    char* end;
+    while (isspace((unsigned char)*str)) str++;
+    if (*str == 0) return;
+    end = str + strlen(str) - 1;
+    while (end > str && isspace((unsigned char)*end)) end--;
+    *(end + 1) = 0;
+}
+
+int startsWith(const char *str, const char *prefix) {
+    if (!str || !prefix) return 0;
+    while (*prefix) {
+        if (*str++ != *prefix++) return 0;
+    }
+    return 1;
+}
+
+char* process_uniform_declarations(char* glslCode) {
+    char* cursor = glslCode;
+    char name[256], type[256], initial_value[1024];
+    int modifiedCodeIndex = 0;
+    size_t maxLength = 1024 * 10;
+    char* modifiedGlslCode = (char*)malloc(maxLength * sizeof(char));
+    if (!modifiedGlslCode) return NULL;
+
+    while (*cursor) {
+        if (strncmp(cursor, "uniform", 7) == 0) {
+            char* cursor_start = cursor;
+
+            cursor += 7;
+
+            while (isspace((unsigned char)*cursor)) cursor++;
+
+            // may be precision qualifier
+            char* precision = NULL;
+            if (startsWith(cursor, "highp")) {
+                precision = " highp";
+                cursor += 5;
+                while (isspace((unsigned char)*cursor)) cursor++;
+            } else if (startsWith(cursor, "lowp")) {
+                precision = " lowp";
+                cursor += 4;
+                while (isspace((unsigned char)*cursor)) cursor++;
+            } else if (startsWith(cursor, "mediump")) {
+                precision = " mediump";
+                cursor += 7;
+                while (isspace((unsigned char)*cursor)) cursor++;
+            }
+
+            int i = 0;
+            while (isalnum((unsigned char)*cursor) || *cursor == '_') {
+                type[i++] = *cursor++;
+            }
+            type[i] = '\0';
+
+            while (isspace((unsigned char)*cursor)) cursor++;
+
+            // may be precision qualifier
+            if(!precision)
+            {
+                if (startsWith(cursor, "highp")) {
+                    precision = " highp";
+                    cursor += 5;
+                    while (isspace((unsigned char)*cursor)) cursor++;
+                } else if (startsWith(cursor, "lowp")) {
+                    precision = " lowp";
+                    cursor += 4;
+                    while (isspace((unsigned char)*cursor)) cursor++;
+                } else if (startsWith(cursor, "mediump")) {
+                    precision = " mediump";
+                    cursor += 7;
+                    while (isspace((unsigned char)*cursor)) cursor++;
+                } else {
+                    precision = "";
+                }
+            }
+
+            while (isspace((unsigned char)*cursor)) cursor++;
+
+            i = 0;
+            while (isalnum((unsigned char)*cursor) || *cursor == '_') {
+                name[i++] = *cursor++;
+            }
+            name[i] = '\0';
+            while (isspace((unsigned char)*cursor)) cursor++;
+
+            initial_value[0] = '\0';
+            if (*cursor == '=') {
+                cursor++;
+                i = 0;
+                while (*cursor && *cursor != ';') {
+                    initial_value[i++] = *cursor++;
+                }
+                initial_value[i] = '\0';
+                trim(initial_value);
+            }
+
+            while (*cursor != ';' && *cursor) {
+                cursor++;
+            }
+
+            char* cursor_end = cursor;
+
+            int spaceLeft = maxLength - modifiedCodeIndex;
+            int len = 0;
+
+            if (*initial_value) {
+                len = snprintf(modifiedGlslCode + modifiedCodeIndex, spaceLeft, "uniform%s %s %s;", precision, type, name);
+            } else {
+                // use original declaration
+                size_t length = cursor_end - cursor_start + 1;
+                if (length < spaceLeft) {
+                    memcpy(modifiedGlslCode + modifiedCodeIndex, cursor_start, length);
+                    len = (int)length;
+                } else {
+                    fprintf(stderr, "Error: Not enough space in buffer\n");
+                }
+                // len = snprintf(modifiedGlslCode + modifiedCodeIndex, spaceLeft, "uniform%s %s %s;", precision, type, name);
+            }
+
+            if (len < 0 || len >= spaceLeft) {
+                free(modifiedGlslCode);
+                return NULL;
+            }
+            modifiedCodeIndex += len;
+
+            while (*cursor == ';') cursor++;
+
+        } else {
+            modifiedGlslCode[modifiedCodeIndex++] = *cursor++;
+        }
+
+        if (modifiedCodeIndex >= maxLength - 1) {
+            maxLength *= 2;
+            modifiedGlslCode = (char*)realloc(modifiedGlslCode, maxLength);
+            if (!modifiedGlslCode) return NULL;
+        }
+    }
+
+    modifiedGlslCode[modifiedCodeIndex] = '\0';
+    return modifiedGlslCode;
+}
+
 bool can_run_essl3(int esversion, const char *glsl) {
     int glsl_version;
 
@@ -76,6 +219,7 @@ void glShaderSource(GLuint shader, GLsizei count, const GLchar *const* string, c
             GLint shaderType;
             glGetShaderiv(shader, GL_SHADER_TYPE, &shaderType);
             converted = glsl_version<140?GLSLtoGLSLES_1(source, shaderType):GLSLtoGLSLES_2(source,shaderType,320);
+            converted = process_uniform_declarations(converted);
             LOG_D("\n[INFO] [Shader] Converted Shader source: \n%s", converted);
         }
         if (converted)