Move all crates into a crates directory (#1940)

crates/egui_glow/src/vao.rs

@@ -0,0 +1,154 @@
+#![allow(unsafe_code)]
+
+use glow::HasContext as _;
+
+use crate::check_for_gl_error;
+
+// ----------------------------------------------------------------------------
+
+#[derive(Debug)]
+pub(crate) struct BufferInfo {
+    pub location: u32, //
+    pub vector_size: i32,
+    pub data_type: u32, //GL_FLOAT,GL_UNSIGNED_BYTE
+    pub normalized: bool,
+    pub stride: i32,
+    pub offset: i32,
+}
+
+// ----------------------------------------------------------------------------
+
+/// Wrapper around either Emulated VAO or GL's VAO.
+pub(crate) struct VertexArrayObject {
+    // If `None`, we emulate VAO:s.
+    vao: Option<crate::glow::VertexArray>,
+    vbo: glow::Buffer,
+    buffer_infos: Vec<BufferInfo>,
+}
+
+impl VertexArrayObject {
+    #[allow(clippy::needless_pass_by_value)] // false positive
+    pub(crate) unsafe fn new(
+        gl: &glow::Context,
+        vbo: glow::Buffer,
+        buffer_infos: Vec<BufferInfo>,
+    ) -> Self {
+        let vao = if supports_vao(gl) {
+            let vao = gl.create_vertex_array().unwrap();
+            check_for_gl_error!(gl, "create_vertex_array");
+
+            // Store state in the VAO:
+            gl.bind_vertex_array(Some(vao));
+            gl.bind_buffer(glow::ARRAY_BUFFER, Some(vbo));
+
+            for attribute in &buffer_infos {
+                gl.vertex_attrib_pointer_f32(
+                    attribute.location,
+                    attribute.vector_size,
+                    attribute.data_type,
+                    attribute.normalized,
+                    attribute.stride,
+                    attribute.offset,
+                );
+                check_for_gl_error!(gl, "vertex_attrib_pointer_f32");
+                gl.enable_vertex_attrib_array(attribute.location);
+                check_for_gl_error!(gl, "enable_vertex_attrib_array");
+            }
+
+            gl.bind_vertex_array(None);
+
+            Some(vao)
+        } else {
+            tracing::debug!("VAO not supported");
+            None
+        };
+
+        Self {
+            vao,
+            vbo,
+            buffer_infos,
+        }
+    }
+
+    pub(crate) unsafe fn bind(&self, gl: &glow::Context) {
+        if let Some(vao) = self.vao {
+            gl.bind_vertex_array(Some(vao));
+            check_for_gl_error!(gl, "bind_vertex_array");
+        } else {
+            gl.bind_buffer(glow::ARRAY_BUFFER, Some(self.vbo));
+            check_for_gl_error!(gl, "bind_buffer");
+
+            for attribute in &self.buffer_infos {
+                gl.vertex_attrib_pointer_f32(
+                    attribute.location,
+                    attribute.vector_size,
+                    attribute.data_type,
+                    attribute.normalized,
+                    attribute.stride,
+                    attribute.offset,
+                );
+                check_for_gl_error!(gl, "vertex_attrib_pointer_f32");
+                gl.enable_vertex_attrib_array(attribute.location);
+                check_for_gl_error!(gl, "enable_vertex_attrib_array");
+            }
+        }
+    }
+
+    pub(crate) unsafe fn unbind(&self, gl: &glow::Context) {
+        if self.vao.is_some() {
+            gl.bind_vertex_array(None);
+        } else {
+            gl.bind_buffer(glow::ARRAY_BUFFER, None);
+            for attribute in &self.buffer_infos {
+                gl.disable_vertex_attrib_array(attribute.location);
+            }
+        }
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+fn supports_vao(gl: &glow::Context) -> bool {
+    const WEBGL_PREFIX: &str = "WebGL ";
+    const OPENGL_ES_PREFIX: &str = "OpenGL ES ";
+
+    let version_string = unsafe { gl.get_parameter_string(glow::VERSION) };
+    tracing::debug!("GL version: {:?}.", version_string);
+
+    // Examples:
+    // * "WebGL 2.0 (OpenGL ES 3.0 Chromium)"
+    // * "WebGL 2.0"
+
+    if let Some(pos) = version_string.rfind(WEBGL_PREFIX) {
+        let version_str = &version_string[pos + WEBGL_PREFIX.len()..];
+        if version_str.contains("1.0") {
+            // need to test OES_vertex_array_object .
+            let supported_extensions = gl.supported_extensions();
+            tracing::debug!("Supported OpenGL extensions: {:?}", supported_extensions);
+            supported_extensions.contains("OES_vertex_array_object")
+        } else {
+            true
+        }
+    } else if version_string.contains(OPENGL_ES_PREFIX) {
+        // glow targets es2.0+ so we don't concern about OpenGL ES-CM,OpenGL ES-CL
+        if version_string.contains("2.0") {
+            // need to test OES_vertex_array_object .
+            let supported_extensions = gl.supported_extensions();
+            tracing::debug!("Supported OpenGL extensions: {:?}", supported_extensions);
+            supported_extensions.contains("OES_vertex_array_object")
+        } else {
+            true
+        }
+    } else {
+        // from OpenGL 3 vao into core
+        if version_string.starts_with('2') {
+            // I found APPLE_vertex_array_object , GL_ATI_vertex_array_object ,ARB_vertex_array_object
+            // but APPLE's and ATI's very old extension.
+            let supported_extensions = gl.supported_extensions();
+            tracing::debug!("Supported OpenGL extensions: {:?}", supported_extensions);
+            supported_extensions.contains("ARB_vertex_array_object")
+        } else {
+            true
+        }
+    }
+}