From 867daf817bba83ab22c5e04409c4afb1075dd158 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 4 Dec 2022 17:00:54 +0000
Subject: Support saving a depth texture

---
 gfx/gl/shadowMapper.cpp |  1 -
 gfx/models/texture.cpp  | 23 +++++++++++++++++++----
 gfx/models/texture.h    |  4 ++++
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/gfx/gl/shadowMapper.cpp b/gfx/gl/shadowMapper.cpp
index a74f3dd..1169524 100644
--- a/gfx/gl/shadowMapper.cpp
+++ b/gfx/gl/shadowMapper.cpp
@@ -51,7 +51,6 @@ ShadowMapper::update(const SceneProvider & scene, const glm::vec3 & dir) const
 	scene.shadows(*this);
 	glCullFace(GL_BACK);
 
-	// Texture::saveDepth(depthMap, size, "/tmp/depth.tga");
 	return lightViewProjection;
 }
 
diff --git a/gfx/models/texture.cpp b/gfx/models/texture.cpp
index 313b3fa..645920f 100644
--- a/gfx/models/texture.cpp
+++ b/gfx/models/texture.cpp
@@ -41,15 +41,30 @@ Texture::bind(GLenum unit) const
 }
 
 void
-Texture::save(const glTexture & texture, const glm::ivec2 & size, const char * path)
+Texture::save(const glTexture & texture, GLenum format, const glm::ivec2 & size, unsigned short channels,
+		const char * path, short tgaFormat)
 {
-	std::vector<unsigned char> buffer(static_cast<size_t>(size.x * size.y * 3));
-	glGetTextureImage(texture, 0, GL_BGR, GL_UNSIGNED_BYTE, static_cast<GLsizei>(buffer.size()), buffer.data());
+	using PixelData = std::vector<unsigned char>;
+	PixelData buffer(static_cast<size_t>(size.x * size.y * channels));
+	glGetTextureImage(texture, 0, format, GL_UNSIGNED_BYTE, static_cast<GLsizei>(buffer.size()), buffer.data());
 
 	auto out = open(path, O_WRONLY | O_CREAT, 0660);
-	short TGAhead[] = {0, 2, 0, 0, 0, 0, static_cast<short>(size.x), static_cast<short>(size.y), 24};
+	const short TGAhead[] = {0, tgaFormat, 0, 0, 0, 0, static_cast<short>(size.x), static_cast<short>(size.y),
+			static_cast<short>(8 * channels)};
 	std::ignore = write(out, &TGAhead, sizeof(TGAhead));
 	std::ignore = write(out, buffer.data(), buffer.size());
 	std::ignore = ftruncate(out, static_cast<off_t>(buffer.size() + sizeof(TGAhead)));
 	close(out);
 }
+
+void
+Texture::save(const glTexture & texture, const glm::ivec2 & size, const char * path)
+{
+	save(texture, GL_BGR, size, 3, path, 2);
+}
+
+void
+Texture::saveDepth(const glTexture & texture, const glm::ivec2 & size, const char * path)
+{
+	save(texture, GL_DEPTH_COMPONENT, size, 1, path, 3);
+}
diff --git a/gfx/models/texture.h b/gfx/models/texture.h
index 09538b3..de532a5 100644
--- a/gfx/models/texture.h
+++ b/gfx/models/texture.h
@@ -19,7 +19,11 @@ public:
 	void bind(GLenum unit = GL_TEXTURE0) const;
 
 	static void save(const glTexture &, const glm::ivec2 & size, const char * path);
+	static void saveDepth(const glTexture &, const glm::ivec2 & size, const char * path);
 
 private:
+	static void save(const glTexture &, GLenum, const glm::ivec2 & size, unsigned short channels, const char * path,
+			short tgaFormat);
+
 	glTexture m_texture;
 };
-- 
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