API for Uniform Block Objects

kitty/gl.h

@@ -425,6 +425,16 @@ GetUniformLocation(PyObject UNUSED *self, PyObject *args) {
     return PyLong_FromLong((long) ans);
 }
 
+static PyObject* 
+GetUniformBlockIndex(PyObject UNUSED *self, PyObject *args) {
+    char *name;
+    unsigned int program_id;
+    if(!PyArg_ParseTuple(args, "Is", &program_id, &name)) return NULL;
+    GLuint ans = glGetUniformBlockIndex(program_id, name);
+    if (ans == GL_INVALID_INDEX) { PyErr_SetString(PyExc_ValueError, "No such uniform block is active"); return NULL; }
+    return PyLong_FromUnsignedLong((unsigned long) ans);
+}
+
 static PyObject* 
 GetAttribLocation(PyObject UNUSED *self, PyObject *args) {
     char *name;
@@ -435,6 +445,44 @@ GetAttribLocation(PyObject UNUSED *self, PyObject *args) {
     return PyLong_FromLong((long) ans);
 }
 
+static PyObject* 
+get_uniform_block_size(PyObject UNUSED *self, PyObject *args) {
+    unsigned int program_id, block_index;
+    if(!PyArg_ParseTuple(args, "II", &program_id, &block_index)) return NULL;
+    GLint ans;
+    glGetActiveUniformBlockiv(program_id, block_index, GL_UNIFORM_BLOCK_DATA_SIZE, &ans);
+    CHECK_ERROR;
+    return PyLong_FromLong((long) ans);
+}
+
+static PyObject* 
+get_uniform_block_offsets(PyObject UNUSED *self, PyObject *args) {
+    unsigned int program_id;
+    PyObject *pynames;
+    if(!PyArg_ParseTuple(args, "IO", &program_id, &pynames)) return NULL;
+    if (!PySequence_Check(pynames)) { PyErr_SetString(PyExc_TypeError, "names must be a sequence"); return NULL; }
+    GLsizei count = PySequence_Size(pynames);
+    char **names = PyMem_Calloc(count, sizeof(char*));
+    GLuint *indices = PyMem_Calloc(count, sizeof(GLuint));
+    GLint *offsets = PyMem_Calloc(count, sizeof(GLint));
+    PyObject *ans = PyTuple_New(count);
+    if (ans == NULL || indices == NULL || names == NULL) return PyErr_NoMemory();
+    for (GLsizei i = 0; i < count; i++) { 
+        PyObject *t = PySequence_ITEM(pynames, i);
+        names[i] = PyUnicode_AsUTF8(t);
+        Py_CLEAR(t);
+    }
+    glGetUniformIndices(program_id, count, (const GLchar * const*)names, indices);
+    glGetActiveUniformsiv(program_id, count, indices, GL_UNIFORM_OFFSET, offsets);
+    for (GLsizei i = 0; i < count; i++) PyTuple_SET_ITEM(ans, i, PyLong_FromLong(offsets[i]));
+    PyMem_Free(names); PyMem_Free(indices); PyMem_Free(offsets);
+    if (_enable_error_checking) { 
+        SET_GL_ERR; 
+        if (PyErr_Occurred()) { Py_CLEAR(ans); return NULL; }
+    }
+    return ans;
+}
+ 
 static PyObject* 
 UseProgram(PyObject UNUSED *self, PyObject *val) {
     unsigned long program_id = PyLong_AsUnsignedLong(val);
@@ -620,6 +668,15 @@ BindBuffer(PyObject UNUSED *self, PyObject *args) {
     Py_RETURN_NONE;
 }
 
+static PyObject* 
+BindBufferBase(PyObject UNUSED *self, PyObject *args) {
+    int tgt; unsigned int index, buf_id;
+    if (!PyArg_ParseTuple(args, "iII", &tgt, &index, &buf_id)) return NULL;
+    glBindBufferBase(tgt, index, buf_id);
+    CHECK_ERROR;
+    Py_RETURN_NONE;
+}
+
 static PyObject* 
 TexBuffer(PyObject UNUSED *self, PyObject *args) {
     int tgt, fmt; unsigned int buf_id;
@@ -777,7 +834,7 @@ int add_module_gl_constants(PyObject *module) {
     GLC(GL_R8); GLC(GL_RED); GLC(GL_UNSIGNED_BYTE); GLC(GL_R32UI); GLC(GL_RGB32UI); GLC(GL_RGBA);
     GLC(GL_TEXTURE_BUFFER); GLC(GL_STATIC_DRAW); GLC(GL_STREAM_DRAW);
     GLC(GL_SRC_ALPHA); GLC(GL_ONE_MINUS_SRC_ALPHA);
-    GLC(GL_BLEND); GLC(GL_FLOAT); GLC(GL_UNSIGNED_INT); GLC(GL_ARRAY_BUFFER);
+    GLC(GL_BLEND); GLC(GL_FLOAT); GLC(GL_UNSIGNED_INT); GLC(GL_ARRAY_BUFFER); GLC(GL_UNIFORM_BUFFER);
     return 1;
 }
 
@@ -788,6 +845,8 @@ int add_module_gl_constants(PyObject *module) {
     {"replace_or_create_buffer", (PyCFunction)replace_or_create_buffer, METH_VARARGS, NULL}, \
     {"glewInit", (PyCFunction)_glewInit, METH_NOARGS, NULL}, \
     {"check_for_extensions", (PyCFunction)check_for_extensions, METH_NOARGS, NULL}, \
+    {"get_uniform_block_size", (PyCFunction)get_uniform_block_size, METH_VARARGS, NULL}, \
+    {"get_uniform_block_offsets", (PyCFunction)get_uniform_block_offsets, METH_VARARGS, NULL}, \
     METH(Viewport, METH_VARARGS) \
     METH(CheckError, METH_NOARGS) \
     METH(ClearColor, METH_VARARGS) \
@@ -802,6 +861,7 @@ int add_module_gl_constants(PyObject *module) {
     METH(Uniform4f, METH_VARARGS) \
     METH(Uniform3fv, METH_VARARGS) \
     METH(GetUniformLocation, METH_VARARGS) \
+    METH(GetUniformBlockIndex, METH_VARARGS) \
     METH(GetAttribLocation, METH_VARARGS) \
     METH(ShaderSource, METH_VARARGS) \
     METH(CompileShader, METH_O) \
@@ -837,6 +897,7 @@ int add_module_gl_constants(PyObject *module) {
     METH(TexParameteri, METH_VARARGS) \
     METH(PixelStorei, METH_VARARGS) \
     METH(BindBuffer, METH_VARARGS) \
+    METH(BindBufferBase, METH_VARARGS) \
     METH(TexBuffer, METH_VARARGS) \
     METH(TexStorage3D, METH_VARARGS) \
     METH(CopyImageSubData, METH_VARARGS) \

kitty/shaders.py

@@ -4,6 +4,7 @@
 
 import os
 import sys
+from collections import namedtuple
 from contextlib import contextmanager
 from ctypes import addressof, sizeof
 from functools import lru_cache
@@ -15,17 +16,19 @@ from .fast_data_types import (
     GL_MAX_TEXTURE_SIZE, GL_NEAREST, GL_R8, GL_RED, GL_STREAM_DRAW,
     GL_TEXTURE0, GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER,
     GL_TEXTURE_MIN_FILTER, GL_TEXTURE_WRAP_S, GL_TEXTURE_WRAP_T, GL_TRUE,
-    GL_UNPACK_ALIGNMENT, GL_UNSIGNED_BYTE, GL_VERTEX_SHADER, ITALIC, SpriteMap,
+    GL_UNIFORM_BUFFER, GL_UNPACK_ALIGNMENT, GL_UNSIGNED_BYTE, GL_VERTEX_SHADER,
-    copy_image_sub_data, glActiveTexture, glAttachShader, glBindBuffer,
+    ITALIC, SpriteMap, copy_image_sub_data, get_uniform_block_offsets,
-    glBindTexture, glBindVertexArray, glCompileShader, glCopyImageSubData,
+    get_uniform_block_size, glActiveTexture, glAttachShader, glBindBuffer,
-    glCreateProgram, glCreateShader, glDeleteBuffer, glDeleteProgram,
+    glBindBufferBase, glBindTexture, glBindVertexArray, glCompileShader,
-    glDeleteShader, glDeleteTexture, glDeleteVertexArray,
+    glCopyImageSubData, glCreateProgram, glCreateShader, glDeleteBuffer,
+    glDeleteProgram, glDeleteShader, glDeleteTexture, glDeleteVertexArray,
     glEnableVertexAttribArray, glGenBuffers, glGenTextures, glGenVertexArrays,
     glGetAttribLocation, glGetBufferSubData, glGetIntegerv,
     glGetProgramInfoLog, glGetProgramiv, glGetShaderInfoLog, glGetShaderiv,
-    glGetUniformLocation, glLinkProgram, glPixelStorei, glShaderSource,
+    glGetUniformBlockIndex, glGetUniformLocation, glLinkProgram, glPixelStorei,
-    glTexParameteri, glTexStorage3D, glTexSubImage3D, glUseProgram,
+    glShaderSource, glTexParameteri, glTexStorage3D, glTexSubImage3D,
-    glVertexAttribDivisor, glVertexAttribPointer, replace_or_create_buffer
+    glUseProgram, glVertexAttribDivisor, glVertexAttribPointer,
+    replace_or_create_buffer
 )
 from .fonts.render import render_cell
 from .utils import safe_print
@@ -34,6 +37,7 @@ GL_VERSION = (3, 3)
 VERSION = GL_VERSION[0] * 100 + GL_VERSION[1] * 10
 ITALIC_MASK = 1 << ITALIC
 BOLD_MASK = 1 << BOLD
+UBO = namedtuple('UBO', 'size index offsets buf_id')
 BASE = os.path.dirname(os.path.abspath(__file__))
 
 
@@ -327,6 +331,30 @@ class ShaderProgram:  # {{{
         ' Return the id for the uniform variable `name` or -1 if not found. '
         return glGetUniformLocation(self.program_id, name)
 
+    @lru_cache(maxsize=2**6)
+    def uniform_block_index(self, name: str) -> int:
+        ' Return the block index for the specified uniform block raises ValueError if not found. '
+        return glGetUniformBlockIndex(self.program_id, name)
+
+    def uniform_block_size(self, block_index):
+        return get_uniform_block_size(self.program_id, block_index)
+
+    def init_uniform_block(self, name, *variables):
+        idx = self.uniform_block_index(name)
+        size = self.uniform_block_size(idx)
+        offsets = get_uniform_block_offsets(self.program_id, variables)
+        offsets = dict(zip(variables, offsets))
+        buf_id = buffer_manager.create(GL_UNIFORM_BUFFER)
+        return UBO(size=size, index=idx, offsets=offsets, buf_id=buf_id)
+
+    def send_uniform_buffer_data(self, ubo, data, usage=GL_STREAM_DRAW):
+        buffer_manager.set_data(ubo.buf_id, data, usage=usage)
+
+    @contextmanager
+    def bound_uniform_buffer(self, ubo):
+        glBindBufferBase(GL_UNIFORM_BUFFER, ubo.index, ubo.buf_id)
+        yield
+
     @lru_cache(maxsize=2**6)
     def attribute_location(self, name: str) -> int:
         ' Return the id for the attribute variable `name` or -1 if not found. '