Implement dirty ANGLE depth clear workaround

ltw/src/main/tinywrapper/Android.mk

@@ -396,6 +396,7 @@ LOCAL_SRC_FILES := \
     basevertex.c \
     blending.c \
     query.c \
+    depth.c \
     shader_wrapper.c \
     string_utils.c \
     framebuffer.c \

ltw/src/main/tinywrapper/depth.c

@@ -0,0 +1,86 @@
+//
+// Created by whbex on 29.12.2025.
+//
+
+#include "egl.h"
+#include "GL/gl.h"
+#include "GL/glext.h"
+#include "string.h"
+
+const char * v_shader_source = ""
+                             "#version 300 es\n"
+                             "void main() {\n"
+                             "gl_Position = vec4(2.0 * vec2(gl_VertexID % 2, gl_VertexID / 2) - 1.0, 0.0, 1.0);\n"
+                             "}\0";
+const char * f_shader_source = "#version 300 es\n"
+                               "void main() {\n"
+                               "}\0";
+
+static GLuint current_program = 0;
+static GLuint current_vao = 0;
+
+static GLuint build_shader(GLuint program, GLenum type, const char* source){
+    GLuint shader = es3_functions.glCreateShader(type);
+    es3_functions.glShaderSource(shader, 1, &source, NULL);
+    es3_functions.glCompileShader(shader);
+    GLint status;
+    char log[512];
+    es3_functions.glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
+    if (!status){
+        printf("LTW: Depth clear shader compile failed!\n");
+        es3_functions.glGetShaderInfoLog(shader, sizeof(log), NULL,log);
+        printf("LTW: Compile log: %s\n", log);
+        return shader;
+    }
+    es3_functions.glAttachShader(program, shader);
+    return shader;
+}
+
+void depthfix_init_program(){
+    if (!current_context->clear_depth_emu) return;
+
+    current_program = es3_functions.glCreateProgram();
+    GLuint vertex = build_shader(current_program, GL_VERTEX_SHADER, v_shader_source);
+    GLuint frag = build_shader(current_program, GL_FRAGMENT_SHADER, f_shader_source);
+    es3_functions.glLinkProgram(current_program);
+    es3_functions.glDeleteShader(vertex);
+    es3_functions.glDeleteShader(frag);
+
+    es3_functions.glGenVertexArrays(1, &current_vao);
+}
+
+void glClear(GLbitfield mask){
+    if (!current_context->clear_depth_emu) goto real;
+  //  printf("LTW: CLEAR BEGIN!!");
+    if (mask != GL_DEPTH_BUFFER_BIT) goto real;
+
+    // This is hard
+    GLint depth_func;
+    GLboolean depth_mask;
+    GLboolean color_mask[4];
+    es3_functions.glGetIntegerv(GL_DEPTH_FUNC, &depth_func);
+    es3_functions.glGetBooleanv(GL_DEPTH_WRITEMASK, &depth_mask);
+    es3_functions.glGetBooleanv(GL_COLOR_WRITEMASK, color_mask);
+    es3_functions.glDepthFunc(GL_ALWAYS);
+    es3_functions.glEnable(GL_DEPTH_TEST);
+    es3_functions.glDepthMask(GL_TRUE);
+    es3_functions.glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);
+
+    es3_functions.glUseProgram(current_program);
+    es3_functions.glBindVertexArray(current_vao);
+    es3_functions.glDrawArrays(GL_QUADS, 0, 4);
+    es3_functions.glUseProgram(0);
+    es3_functions.glBindVertexArray(0);
+   // printf("LTW: CLEAR END!!");
+
+
+    es3_functions.glDisable(GL_DEPTH_TEST);
+    es3_functions.glDepthFunc(depth_func);
+    es3_functions.glDepthMask(depth_mask);
+   // es3_functions.glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+    es3_functions.glColorMask(color_mask[0], color_mask[1], color_mask[2], color_mask[3]);
+
+    return;
+    real:
+    es3_functions.glClear(mask);
+}

ltw/src/main/tinywrapper/depth.h

@@ -0,0 +1,10 @@
+//
+// Created by whbex on 29.12.2025.
+//
+
+#ifndef POJAVLAUNCHER_DEPTH_H
+#define POJAVLAUNCHER_DEPTH_H
+
+void depthfix_init_program();
+
+#endif //POJAVLAUNCHER_DEPTH_H

ltw/src/main/tinywrapper/egl.c

@@ -7,6 +7,7 @@
 #include "unordered_map/int_hash.h"
 #include "string_utils.h"
 #include "env.h"
+#include "depth.h"
 #include <string.h>
 
 thread_local context_t *current_context;
@@ -212,6 +213,11 @@ static void init_incontext(context_t* tw_context) {
     basevertex_init(tw_context);
     buffer_copier_init(tw_context);
     es3_functions.glGenBuffers(1, &tw_context->multidraw_element_buffer);
+    if(env_istrue_d("LTW_EMULATE_DEPTHCLEAR", false)){
+        printf("LTW: Enabling ANGLE depth clear workaround\n");
+        tw_context->clear_depth_emu = true;
+        depthfix_init_program();
+    }
 }
 
 EGLContext eglCreateContext(EGLDisplay dpy, EGLConfig config, EGLContext share_context, const EGLint *attrib_list) {

ltw/src/main/tinywrapper/egl.h

@@ -69,7 +69,7 @@ typedef struct {
 typedef struct {
     EGLContext phys_context;
     bool context_rdy;
-    bool es31, es32, buffer_storage, buffer_texture_ext, multidraw_indirect, timer_query;
+    bool es31, es32, buffer_storage, buffer_texture_ext, multidraw_indirect, timer_query, clear_depth_emu;
     GLint shader_version;
     basevertex_renderer_t basevertex;
     PFNGLDRAWELEMENTSBASEVERTEXPROC drawelementsbasevertex;

ltw/src/main/tinywrapper/es3_overrides.h

@@ -132,4 +132,5 @@ GLESOVERRIDE(glGetError)
 GLESOVERRIDE(glTexBuffer)
 GLESOVERRIDE(glTexBufferRange)
 GLESOVERRIDE(glMapBufferRange)
-GLESOVERRIDE(glFlushMappedBufferRange)
+GLESOVERRIDE(glFlushMappedBufferRange)
+GLESOVERRIDE(glClear)