Refactor renderer functions out of main.rs

This moves the rendering logic to draw the grid, to draw strings, and to
draw the cursor into the renderere module. In addition to being an
organizational improvement, this also allowed for some optimizations
managing OpenGL state. Render times for a moderate screen of text
dropped from ~10ms to ~4ms.

1 files changed, 103 insertions, 19 deletions

diff --git a/src/renderer/mod.rs b/src/renderer/mod.rs
index 9495d8a0..b5c04a42 100644
--- a/src/renderer/mod.rs
+++ b/src/renderer/mod.rs
@@ -2,16 +2,16 @@ use std::ffi::CString;
 use std::mem::size_of;
 use std::ptr;
 
-use gl;
-use cgmath;
-
+use cgmath::{self, Matrix};
 use euclid::{Rect, Size2D, Point2D};
-
 use gl::types::*;
-
-use cgmath::Matrix;
+use gl;
 
 use text::RasterizedGlyph;
+use grid::Grid;
+use term;
+
+use super::{Rgb, TermProps, GlyphCache};
 
 static TEXT_SHADER_V: &'static str = include_str!("../../res/text.v.glsl");
 static TEXT_SHADER_F: &'static str = include_str!("../../res/text.f.glsl");
@@ -21,6 +21,7 @@ pub struct QuadRenderer {
     vao: GLuint,
     vbo: GLuint,
     ebo: GLuint,
+    active_color: Rgb,
 }
 
 #[allow(dead_code)]
@@ -32,7 +33,6 @@ pub struct PackedVertex {
     v: f32,
 }
 
-use super::Rgb;
 
 impl QuadRenderer {
     // TODO should probably hand this a transform instead of width/height
@@ -91,14 +91,101 @@ impl QuadRenderer {
             vao: vao,
             vbo: vbo,
             ebo: ebo,
+            active_color: Rgb { r: 0, g: 0, b: 0 },
+        }
+    }
+
+    /// Render a string in a predefined location. Used for printing render time for profiling and
+    /// optimization.
+    pub fn render_string(&mut self,
+                     s: &str,
+                     glyph_cache: &GlyphCache,
+                     cell_width: u32,
+                     color: &Rgb)
+    {
+        self.prepare_render();
+
+        let (mut x, mut y) = (200f32, 20f32);
+
+        for c in s.chars() {
+            if let Some(glyph) = glyph_cache.get(&c) {
+                self.render(glyph, x, y, color);
+            }
+
+            x += cell_width as f32 + 2f32;
+        }
+
+        self.finish_render();
+    }
+
+    pub fn render_cursor(&mut self,
+                         cursor: term::Cursor,
+                         glyph_cache: &GlyphCache,
+                         props: &TermProps)
+    {
+        self.prepare_render();
+        if let Some(glyph) = glyph_cache.get(&term::CURSOR_SHAPE) {
+            let y = (props.cell_height + props.sep_y) * (cursor.y as f32);
+            let x = (props.cell_width + props.sep_x) * (cursor.x as f32);
+
+            let y_inverted = props.height - y - props.cell_height;
+
+            self.render(glyph, x, y_inverted, &term::DEFAULT_FG);
+        }
+
+        self.finish_render();
+    }
+
+    pub fn render_grid(&mut self, grid: &Grid, glyph_cache: &GlyphCache, props: &TermProps) {
+        self.prepare_render();
+        for i in 0..grid.rows() {
+            let row = &grid[i];
+            for j in 0..row.cols() {
+                let cell = &row[j];
+                if cell.c != ' ' {
+                    if let Some(glyph) = glyph_cache.get(&cell.c) {
+                        let y = (props.cell_height + props.sep_y) * (i as f32);
+                        let x = (props.cell_width + props.sep_x) * (j as f32);
+
+                        let y_inverted = (props.height) - y - (props.cell_height);
+
+                        self.render(glyph, x, y_inverted, &cell.fg);
+                    }
+                }
+            }
+        }
+        self.finish_render();
+    }
+
+    fn prepare_render(&self) {
+        unsafe {
+            self.program.activate();
+
+            gl::BindVertexArray(self.vao);
+            gl::BindBuffer(gl::ARRAY_BUFFER, self.vbo);
+            gl::BindBuffer(gl::ELEMENT_ARRAY_BUFFER, self.ebo);
         }
     }
 
-    pub fn render(&self, glyph: &Glyph, x: f32, y: f32, color: &Rgb) {
-        self.program.activate();
+    fn finish_render(&self) {
         unsafe {
-            // set color
-            gl::Uniform3i(self.program.u_color, color.r as i32, color.g as i32, color.b as i32);
+            gl::BindBuffer(gl::ELEMENT_ARRAY_BUFFER, 0);
+            gl::BindBuffer(gl::ARRAY_BUFFER, 0);
+            gl::BindVertexArray(0);
+
+            self.program.deactivate();
+        }
+    }
+
+    fn render(&mut self, glyph: &Glyph, x: f32, y: f32, color: &Rgb) {
+        if &self.active_color != color {
+            unsafe {
+                gl::Uniform3i(self.program.u_color,
+                              color.r as i32,
+                              color.g as i32,
+                              color.b as i32);
+            }
+            self.active_color = color.to_owned();
         }
 
         let rect = get_rect(glyph, x, y);
@@ -113,24 +200,16 @@ impl QuadRenderer {
 
         unsafe {
             bind_mask_texture(glyph.tex_id);
-            gl::BindVertexArray(self.vao);
-
-            gl::BindBuffer(gl::ARRAY_BUFFER, self.vbo);
             gl::BufferSubData(
                 gl::ARRAY_BUFFER,
                 0,
                 (packed.len() * size_of::<PackedVertex>()) as isize,
                 packed.as_ptr() as *const _
             );
-            gl::BindBuffer(gl::ARRAY_BUFFER, 0);
-            gl::BindBuffer(gl::ELEMENT_ARRAY_BUFFER, self.ebo);
 
             gl::DrawElements(gl::TRIANGLES, 6, gl::UNSIGNED_INT, ptr::null());
-            gl::BindVertexArray(0);
             gl::BindTexture(gl::TEXTURE_2D, 0);
         }
-
-        self.program.deactivate();
     }
 }
 
@@ -195,6 +274,11 @@ impl ShaderProgram {
         assert!(color != gl::INVALID_VALUE as i32);
         assert!(color != gl::INVALID_OPERATION as i32);
 
+        // Initialize to known color (black)
+        unsafe {
+            gl::Uniform3i(color, 0, 0, 0);
+        }
+
         let shader = ShaderProgram {
             id: program,
             u_projection: projection,