From 1f68fe78e84f25c8ddacdc37a293a5de31725bab Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 1 Jan 2022 13:01:08 +0000
Subject: First iteration with font/text support

---
 gfx/gl/shaders/uiShaderFont.fs | 12 ++++++++++++
 gfx/gl/uiShader.cpp            | 30 +++++++++++++++++++++++-------
 gfx/gl/uiShader.h              |  6 ++++--
 3 files changed, 39 insertions(+), 9 deletions(-)
 create mode 100644 gfx/gl/shaders/uiShaderFont.fs

(limited to 'gfx/gl')

diff --git a/gfx/gl/shaders/uiShaderFont.fs b/gfx/gl/shaders/uiShaderFont.fs
new file mode 100644
index 0000000..bee455d
--- /dev/null
+++ b/gfx/gl/shaders/uiShaderFont.fs
@@ -0,0 +1,12 @@
+#version 130
+
+in vec2 texCoord0;
+
+uniform sampler2D sampler;
+uniform vec3 colour;
+
+void
+main()
+{
+	gl_FragColor = vec4(colour, texture(sampler, texCoord0).r);
+}
diff --git a/gfx/gl/uiShader.cpp b/gfx/gl/uiShader.cpp
index 1c2a0e1..fbcdd15 100644
--- a/gfx/gl/uiShader.cpp
+++ b/gfx/gl/uiShader.cpp
@@ -2,20 +2,36 @@
 #include <gfx/gl/glSource.h>
 #include <gfx/gl/programHandle.h>
 #include <gfx/gl/shaders/fs-uiShader.h>
+#include <gfx/gl/shaders/fs-uiShaderFont.h>
 #include <gfx/gl/shaders/vs-uiShader.h>
 #include <glm/glm.hpp>
 #include <glm/gtc/type_ptr.hpp>
+#include <initializer_list>
 
-UIShader::UIShader(size_t width, size_t height) : program {uiShader_vs.compile(), uiShader_fs.compile()}
+UIShader::UIShader(size_t width, size_t height) :
+	progDefault {uiShader_vs.compile(), uiShader_fs.compile()}, progText {uiShader_vs.compile(),
+																		uiShaderFont_fs.compile()}
 {
-	if (auto loc = glGetUniformLocation(program.m_program, "uiProjection"); loc >= 0) {
-		glUseProgram(program.m_program);
-		const auto uiProjection = glm::ortho<float>(0, static_cast<float>(width), 0, static_cast<float>(height));
-		glUniformMatrix4fv(loc, 1, GL_FALSE, glm::value_ptr(uiProjection));
+	for (const auto prog : {&progDefault, &progText}) {
+		if (auto loc = glGetUniformLocation(prog->m_program, "uiProjection"); loc >= 0) {
+			glUseProgram(prog->m_program);
+			const auto uiProjection = glm::ortho<float>(0, static_cast<float>(width), 0, static_cast<float>(height));
+			glUniformMatrix4fv(loc, 1, GL_FALSE, glm::value_ptr(uiProjection));
+		}
 	}
 }
+
+void
+UIShader::useDefault() const
+{
+	glUseProgram(progDefault.m_program);
+}
+
 void
-UIShader::use() const
+UIShader::useText(glm::vec3 colour) const
 {
-	glUseProgram(program.m_program);
+	glUseProgram(progText.m_program);
+	if (auto loc = glGetUniformLocation(progText.m_program, "colour"); loc >= 0) {
+		glUniform3fv(loc, 1, glm::value_ptr(colour));
+	}
 }
diff --git a/gfx/gl/uiShader.h b/gfx/gl/uiShader.h
index 45ccc23..502ba13 100644
--- a/gfx/gl/uiShader.h
+++ b/gfx/gl/uiShader.h
@@ -4,17 +4,19 @@
 #include "programHandle.h"
 #include <GL/glew.h>
 #include <cstddef>
+#include <glm/glm.hpp>
 
 class UIShader {
 public:
 	UIShader(std::size_t width, std::size_t height);
-	void use() const;
+	void useDefault() const;
+	void useText(glm::vec3) const;
 
 private:
 	class UIProgramHandle : public ProgramHandleBase {
 		using ProgramHandleBase::ProgramHandleBase;
 	};
-	UIProgramHandle program;
+	UIProgramHandle progDefault, progText;
 };
 
 #endif
-- 
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