add support for drawing a mouse area

the bargraph accepts mouse coordinates in the 0.0-1.0 range, and
paints a transparent yellow box over the graph.

6 files changed, 119 insertions, 2 deletions

diff --git a/retrace/daemon/bargraph/glframe_bargraph.cpp b/retrace/daemon/bargraph/glframe_bargraph.cpp
index a902e40d..37aca994 100644
--- a/retrace/daemon/bargraph/glframe_bargraph.cpp
+++ b/retrace/daemon/bargraph/glframe_bargraph.cpp
@@ -59,7 +59,9 @@ BarGraphRenderer::fshader =
     "}";
 
 BarGraphRenderer::BarGraphRenderer(bool invert)
-    : invert_y(invert ? -1 : 1) {
+    : mouse_vertices(4),
+      mouse_area(2),
+      invert_y(invert ? -1 : 1) {
   // generate vbo
   GL::GenBuffers(1, &vbo);
   GL_CHECK();
@@ -151,6 +153,24 @@ BarGraphRenderer::setBars(const std::vector<BarMetrics> &bars) {
 
 void
 BarGraphRenderer::setMouseArea(float x1, float y1, float x2, float y2) {
+  mouse_area[0].x = x1;
+  mouse_area[0].y = y1;
+  mouse_area[1].x = x2;
+  mouse_area[1].y = y2;
+
+  // calculate mouse_vertices based on b
+  mouse_vertices[0].x = x1;
+  mouse_vertices[0].y = y1;
+  mouse_vertices[1].x = x1;
+  mouse_vertices[1].y = y2;
+  mouse_vertices[2].x = x2;
+  mouse_vertices[2].y = y1;
+  mouse_vertices[3].x = x2;
+  mouse_vertices[3].y = y2;
+  for (auto &vertex : mouse_vertices) {
+    vertex.x *= total_x;
+    vertex.y *= max_y;
+  }
 }
 
 // solely for debugging: allows gdb to print vertices[n]
@@ -222,7 +242,31 @@ BarGraphRenderer::render() {
     for (auto &i : outline_indices) {
       i += 4;
     }
-}
+  }
+
+  if ((mouse_area[0].x > 0) ||
+      (mouse_area[0].y > 0) ||
+      (mouse_area[1].x > 0) ||
+      (mouse_area[1].y > 0)) {
+    // mouse selection is active, draw a selection rectangle
+
+    GL::Enable(GL_BLEND);
+    GL_CHECK();
+    GL::BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    GL_CHECK();
+
+    // buffer data to vbo
+    GL::BufferData(GL_ARRAY_BUFFER, mouse_vertices.size() * sizeof(Vertex),
+                   mouse_vertices.data(), GL_STATIC_DRAW);
+    GL_CHECK();
+
+    // yellow selection box
+    const float color[4] = { 1.0, 1.0, 0.0, 0.5 };
+    GL::Uniform4f(uni_bar_color, color[0], color[1], color[2], color[3]);
+    GL_CHECK();
+    GL::DrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    GL_CHECK();
+  }
 
   // disable vbo
   GL::DisableVertexAttribArray(att_coord);
diff --git a/retrace/daemon/bargraph/glframe_bargraph.hpp b/retrace/daemon/bargraph/glframe_bargraph.hpp
index 2a089cec..d4175264 100644
--- a/retrace/daemon/bargraph/glframe_bargraph.hpp
+++ b/retrace/daemon/bargraph/glframe_bargraph.hpp
@@ -68,6 +68,11 @@ class BarGraphRenderer {
   };
 
   std::vector<Vertex> vertices;
+  std::vector<Vertex> mouse_vertices;
+
+  // selection box.  coordinates are in the 0.0 - 1.0 range
+  std::vector<Vertex> mouse_area;
+
   float max_y, total_x, invert_y;
 };
 
diff --git a/retrace/daemon/bargraph/glframe_glhelper.cpp b/retrace/daemon/bargraph/glframe_glhelper.cpp
index fd8ca1a6..b36c1dc9 100644
--- a/retrace/daemon/bargraph/glframe_glhelper.cpp
+++ b/retrace/daemon/bargraph/glframe_glhelper.cpp
@@ -61,6 +61,7 @@ static void *pDisableVertexAttribArray = NULL;
 static void *pEnable = NULL;
 static void *pReadPixels = NULL;
 static void *pDrawElements = NULL;
+static void *pBlendFunc = NULL;
 }  // namespace
 
 void
@@ -129,6 +130,8 @@ GlFunctions::Init(void *lookup_fn) {
   assert(pReadPixels);
   pDrawElements = GetProcAddress("glDrawElements");
   assert(pDrawElements);
+  pBlendFunc = GetProcAddress("glBlendFunc");
+  assert(pBlendFunc);
 }
 
 GLuint
@@ -315,3 +318,9 @@ GlFunctions::DrawElements(GLenum mode, GLsizei count,
                                GLenum type, const GLvoid *indices);
   ((DRAWELEMENTS) pDrawElements)(mode, count, type, indices);
 }
+
+void
+GlFunctions::BlendFunc(GLenum sfactor, GLenum dfactor) {
+  typedef void (*BLENDFUNC)(GLenum sfactor, GLenum dfactor);
+  ((BLENDFUNC) pBlendFunc)(sfactor, dfactor);
+}
diff --git a/retrace/daemon/bargraph/glframe_glhelper.hpp b/retrace/daemon/bargraph/glframe_glhelper.hpp
index da992a56..342e2042 100644
--- a/retrace/daemon/bargraph/glframe_glhelper.hpp
+++ b/retrace/daemon/bargraph/glframe_glhelper.hpp
@@ -80,6 +80,7 @@ class GlFunctions {
                            GLvoid *pixels);
   static void DrawElements(GLenum mode, GLsizei count,
                            GLenum type, const GLvoid *indices);
+  static void BlendFunc(GLenum sfactor, GLenum dfactor);
 
  private:
   GlFunctions();
diff --git a/retrace/daemon/bargraph/glframe_qbargraph.cpp b/retrace/daemon/bargraph/glframe_qbargraph.cpp
index 9e952083..1d391fb1 100644
--- a/retrace/daemon/bargraph/glframe_qbargraph.cpp
+++ b/retrace/daemon/bargraph/glframe_qbargraph.cpp
@@ -45,6 +45,7 @@ QBarGraphRenderer::QBarGraphRenderer() : m_graph(true) {
   metrics[3].metric1 = 2;
   metrics[3].metric2 = 2;
   m_graph.setBars(metrics);
+  m_graph.setMouseArea(.25, .25, .75, .75);
 }
 
 void
diff --git a/retrace/daemon/bargraph/test/test_bargraph.cpp b/retrace/daemon/bargraph/test/test_bargraph.cpp
index f67dbba3..b9eef55f 100644
--- a/retrace/daemon/bargraph/test/test_bargraph.cpp
+++ b/retrace/daemon/bargraph/test/test_bargraph.cpp
@@ -103,3 +103,60 @@ TEST(BarGraph, MultiBar) {
   EXPECT_EQ(data.red, 255);
 }
 
+TEST(BarGraph, BarSpacing) {
+  GlFunctions::Init();
+  TestContext c;
+  BarGraphRenderer r;
+  std::vector<BarMetrics> bars(2);
+  bars[0].metric1 = 25;
+  bars[0].metric2 = 0;
+  bars[1].metric1 = 50;
+  bars[1].metric2 = 0;
+  r.setBars(bars);
+  r.render();
+
+  Pixel data;
+
+  // whitespace should be at center
+  GlFunctions::ReadPixels(500, 2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &data);
+  EXPECT_EQ(data.red, 255);
+  EXPECT_EQ(data.blue, 255);
+  EXPECT_EQ(data.green, 255);
+}
+
+TEST(BarGraph, MouseSelect) {
+  GlFunctions::Init();
+  TestContext c;
+  BarGraphRenderer r;
+  std::vector<BarMetrics> bars(2);
+  bars[0].metric1 = 25;
+  bars[0].metric2 = 0;
+  bars[1].metric1 = 50;
+  bars[1].metric2 = 0;
+  r.setBars(bars);
+  r.setMouseArea(0.25, 0.25, 0.75, 0.75);
+  r.render();
+
+  Pixel data;
+
+  // yellow blended on white should be at center
+  GlFunctions::ReadPixels(500, 500, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &data);
+  EXPECT_EQ(data.red, 255);
+  EXPECT_EQ(data.blue, 255);
+  EXPECT_EQ(data.green, 128);
+  EXPECT_EQ(data.alpha, 255);
+
+  // white should be at the bottom
+  GlFunctions::ReadPixels(500, 2, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &data);
+  EXPECT_EQ(data.red, 255);
+  EXPECT_EQ(data.blue, 255);
+  EXPECT_EQ(data.green, 255);
+  EXPECT_EQ(data.alpha, 255);
+
+  // blend should be on the bar
+  GlFunctions::ReadPixels(300, 300, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &data);
+  EXPECT_EQ(data.red, 128);
+  EXPECT_EQ(data.blue, 128);
+  EXPECT_EQ(data.green, 128);
+  EXPECT_EQ(data.alpha, 255);
+}