[skip ci] really run shader

cmake/TaichiCore.cmake

@@ -88,7 +88,8 @@ if (TI_WITH_CUDA)
     target_link_libraries(${LIBRARY_NAME} ${llvm_ptx_libs})
 endif()
 
-target_link_libraries(${LIBRARY_NAME} /usr/lib/libGLESv2_nvidia.so GLESv2_nvidia)
+#target_link_libraries(${LIBRARY_NAME} /usr/lib/libGL.so GL)
+target_link_libraries(${LIBRARY_NAME} /usr/lib/libGLEW.so GLEW)
 target_link_libraries(${LIBRARY_NAME} /usr/lib/libglfw.so glfw)
 
 # add_executable(runtime runtime/runtime.cpp)

taichi/backends/codegen_opengl.cpp

@@ -47,6 +47,7 @@ class KernelGen : public IRVisitor
   bool is_top_level_{true};
 
   std::string kernel_name_;
+  std::string glsl_kernel_name_;
   std::string glsl_kernel_prefix_;
   int glsl_kernel_count_{0};
 
@@ -71,11 +72,23 @@ class KernelGen : public IRVisitor
   void generate_header()
   {
     emit("#version 430 core");
-    //emit("#version 310 es");
     emit("#extension GL_ARB_compute_shader: enable");
-    emit("layout (location = 0) in float input;");
-    emit("layout (location = 1) out float output;");
     emit("");
+    emit("layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;");
+    emit("");
+    emit("layout(std430, binding = 0) buffer data");
+    emit("{{");
+    emit("  float tmp7;");
+    emit("}};");
+    emit("");
+  }
+
+  void generate_bottom()
+  {
+    emit("void main()");
+    emit("{{");
+    emit("  {}();", glsl_kernel_name_);
+    emit("}}");
   }
 
   void visit(Block *stmt) override
@@ -190,7 +203,7 @@ class KernelGen : public IRVisitor
 
   std::string make_kernel_name()
   {
-    return fmt::format("{}_{}", glsl_kernel_prefix_, glsl_kernel_count_++);
+    return fmt::format("{}{}", glsl_kernel_prefix_, glsl_kernel_count_++);
   }
 
   void emit_glsl_kernel_func_sig(const std::string &kernel_name)
@@ -201,10 +214,10 @@ class KernelGen : public IRVisitor
   void generate_serial_kernel(OffloadedStmt *stmt) {
     TI_ASSERT(stmt->task_type == OffloadedStmt::TaskType::serial);
     const std::string glsl_kernel_name = make_kernel_name();
+    this->glsl_kernel_name_ = glsl_kernel_name;
     emit_glsl_kernel_func_sig(glsl_kernel_name);
     emit("{{ // serial");
     stmt->body->accept(this);
-    emit("output = 233.0;");
     emit("}}\n");
   }
 
@@ -237,6 +250,7 @@ class KernelGen : public IRVisitor
     generate_header();
     irpass::print(kernel->ir);
     kernel->ir->accept(this);
+    generate_bottom();
   }
 };
 

taichi/platform/opengl/opengl_api.cpp

@@ -1,8 +1,9 @@
-//#define USE_GLEW
+#define USE_GLEW
 #ifdef USE_GLEW
+#define GLEW_STATIC
 #include <GL/glew.h>
 #else
-#include <GLES3/gl32.h>
+//#include <GLES3/gl32.h>
 #endif
 #include <GLFW/glfw3.h>
 #include "opengl_api.h"
@@ -37,9 +38,10 @@ struct GLShader
 
   GLShader &compile(const std::string &source)
   {
-    GLsizei length = 1;
-    const GLchar *source_cstr = source.c_str();
-    glShaderSource(id_, 1, &source_cstr, &length);
+    // https://stackoverflow.com/questions/28527956/get-011-error-syntax-error-unexpected-end-when-trying-to-compile-shader
+    GLchar *source_cstr = new GLchar[source.size() + 1];
+    std::strcpy(source_cstr, source.c_str());
+    glShaderSource(id_, 1, &source_cstr, NULL);
     TI_INFO("[glsl] compiling shader:\n{}", source);
     glCompileShader(id_);
     GLint status = GL_TRUE;
@@ -49,7 +51,7 @@ struct GLShader
       glGetShaderiv(id_, GL_INFO_LOG_LENGTH, &logLength);
       GLchar *log = new GLchar[logLength];
       glGetShaderInfoLog(id_, logLength, &logLength, log);
-      TI_ERROR("[glsl] shader compile error: {}", log);
+      TI_ERROR("[glsl] shader compile error:\n{}", log);
     }
     return *this;
   }
@@ -92,7 +94,7 @@ struct GLProgram
       glGetProgramiv(id_, GL_INFO_LOG_LENGTH, &logLength);
       GLchar *log = new GLchar[logLength];
       glGetProgramInfoLog(id_, logLength, &logLength, log);
-      TI_ERROR("[glsl] program link error: {}", log);
+      TI_ERROR("[glsl] program link error:\n{}", log);
     }
     return *this;
   }
@@ -112,53 +114,44 @@ struct GLProgram
 };
 
 // https://blog.csdn.net/ylbs110/article/details/52074826
-struct GLVertexBuffer
+// https://www.khronos.org/opengl/wiki/Shader_Storage_Buffer_Object
+struct GLSSBO
 {
   GLuint id_;
 
-  GLVertexBuffer()
+  GLSSBO()
   {
     glGenBuffers(1, &id_);
   }
 
-  ~GLVertexBuffer()
+  ~GLSSBO()
   {
     glDeleteBuffers(1, &id_);
   }
 
-  GLVertexBuffer &bind()
+  GLSSBO &bind()
   {
-    glBindVertexArray(id_);
+    glBindBuffer(GL_SHADER_STORAGE_BUFFER, id_);
     return *this;
   }
 
-  GLVertexBuffer &delete_VAO() // ???
-  {
-    glDeleteVertexArrays(1, &id_);
-    return *this;
-  }
-
-  GLVertexBuffer &bind_data(void *data, size_t size, GLuint draw_type = GL_STATIC_DRAW)
+  GLSSBO &bind_data(void *data, size_t size, GLuint usage = GL_STATIC_READ)
   {
     this->bind();
-    glBufferData(GL_ARRAY_BUFFER, size, data, draw_type);
+    glBufferData(GL_SHADER_STORAGE_BUFFER, size, data, usage);
     return *this;
   }
 
-  // layout (location = location); type x[count]; and sizeof(x) = size; &x = vao + offset
-  GLVertexBuffer &set_attrib(GLuint type, size_t location, size_t offset, size_t count, size_t size)
+  GLSSBO &bind_base(size_t index)
   {
     this->bind();
-    glVertexAttribPointer(location, count, GL_FLOAT, GL_FALSE, size, NULL);
-    glEnableVertexAttribArray(0);
+    glBindBufferBase(GL_SHADER_STORAGE_BUFFER, index, id_);
     return *this;
   }
 };
 
-void launch_glsl_kernel(std::string source)
+void initialize_opengl()
 {
-  static bool gl_inited = false;
-  if (!gl_inited) {
     TI_INFO("[glsl] initializing GLFW (with hint GL 4.3)");
     glfwInit();
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
@@ -172,23 +165,38 @@ void launch_glsl_kernel(std::string source)
       TI_ERROR("[glsl] cannot initialize GLEW: {}", glewGetErrorString(status));
     }
 #endif
+    const char *gl_version = (const char *)glGetString(GL_VERSION);
+    if (!gl_version) {
+      TI_WARN("[glsl] cannot get GL_VERSION");
+    } else {
+      TI_INFO("[glsl] GL_VERSION: {}", gl_version);
+    }
+}
+
+void launch_glsl_kernel(std::string source)
+{
+  static bool gl_inited = false;
+  if (!gl_inited) {
+    initialize_opengl();
     gl_inited = true;
   }
   GLShader shader(source);
   GLProgram program(shader);
   program.link();
   program.use();
 
-  GLVertexBuffer vbo;
-  float data[2] = {0.5, 0.0};
-  vbo.bind_data(data, sizeof(data));
-  vbo.set_attrib(GL_FLOAT, 0, 0, 1, 1 * sizeof(float));
-  vbo.set_attrib(GL_FLOAT, 1, 1, 1, 1 * sizeof(float));
-  TI_INFO("[glsl] output before: {}", data[1]);
+  struct {
+    float number;
+  } data;
+  data.number = 233.3;
+  GLSSBO ssbo;
+  ssbo.bind_data(&data, sizeof(data), GL_DYNAMIC_READ);
+  ssbo.bind_base(0);
+
   TI_INFO("[glsl] dispatching compute...");
   // https://www.khronos.org/opengl/wiki/Compute_Shader
   glDispatchCompute(1, 1, 1);
-  TI_INFO("[glsl] output after: {}", data[1]);
+  TI_INFO("[glsl] data.number = {}", data.number);
 }
 
 bool is_opengl_api_available()